diff --git a/Anchor.toml b/Anchor.toml
index 32869301..21ad41fe 100644
--- a/Anchor.toml
+++ b/Anchor.toml
@@ -6,7 +6,6 @@ types = "sdk/solana/tbrv3/idl"
 
 [features]
 resolution = true
-skip-lint = true
 
 [programs.localnet]
 #token_bridge_relayer = "7TLiBkpDGshV4o3jmacTCx93CLkmo3VjZ111AsijN9f8"
diff --git a/sdk/solana/tbrv3/idl/token_bridge_relayer.ts b/sdk/solana/tbrv3/idl/token_bridge_relayer.ts
index 360f6270..bad574fe 100644
--- a/sdk/solana/tbrv3/idl/token_bridge_relayer.ts
+++ b/sdk/solana/tbrv3/idl/token_bridge_relayer.ts
@@ -116,6 +116,116 @@ export type TokenBridgeRelayer = {
             "because we will update roles depending on the operation."
           ],
           "writable": true
+        },
+        {
+          "name": "upgradeLock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "name": "programData",
+          "writable": true,
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  13,
+                  74,
+                  247,
+                  118,
+                  36,
+                  164,
+                  201,
+                  97,
+                  25,
+                  221,
+                  241,
+                  144,
+                  142,
+                  148,
+                  63,
+                  218,
+                  160,
+                  137,
+                  78,
+                  28,
+                  18,
+                  140,
+                  195,
+                  112,
+                  127,
+                  26,
+                  150,
+                  227,
+                  211,
+                  125,
+                  216,
+                  108
+                ]
+              }
+            ],
+            "program": {
+              "kind": "const",
+              "value": [
+                2,
+                168,
+                246,
+                145,
+                78,
+                136,
+                161,
+                176,
+                226,
+                16,
+                21,
+                62,
+                247,
+                99,
+                174,
+                43,
+                0,
+                194,
+                185,
+                61,
+                22,
+                193,
+                36,
+                210,
+                192,
+                83,
+                122,
+                16,
+                4,
+                128,
+                0,
+                0
+              ]
+            }
+          }
+        },
+        {
+          "name": "bpfLoaderUpgradeable",
+          "address": "BPFLoaderUpgradeab1e11111111111111111111111"
         }
       ],
       "args": []
@@ -287,7 +397,10 @@ export type TokenBridgeRelayer = {
           "writable": true
         },
         {
-          "name": "peer"
+          "name": "peer",
+          "docs": [
+            "The TBR peer (_i.e._ `data().from_address()`). We do not care about the Token Bridge peer `vaa.meta.emitter_address`."
+          ]
         },
         {
           "name": "tokenBridgeConfig"
@@ -437,10 +550,6 @@ export type TokenBridgeRelayer = {
             ]
           }
         },
-        {
-          "name": "previousOwner",
-          "signer": true
-        },
         {
           "name": "authBadgePreviousOwner",
           "writable": true,
@@ -477,6 +586,30 @@ export type TokenBridgeRelayer = {
           ],
           "writable": true
         },
+        {
+          "name": "upgradeLock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
         {
           "name": "programData",
           "writable": true,
@@ -593,10 +726,7 @@ export type TokenBridgeRelayer = {
           "signer": true
         },
         {
-          "name": "owner",
-          "docs": [
-            "The designated owner of the program."
-          ]
+          "name": "owner"
         },
         {
           "name": "authBadge",
@@ -628,7 +758,7 @@ export type TokenBridgeRelayer = {
           "name": "tbrConfig",
           "docs": [
             "Owner Config account. This program requires that the `owner` specified",
-            "in the context equals the pubkey specified in this account. Mutable."
+            "in the context equals the pubkey specified in this account."
           ],
           "writable": true,
           "pda": {
@@ -824,13 +954,6 @@ export type TokenBridgeRelayer = {
             "Proof that the signer is authorized."
           ]
         },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Owner Config account. This program requires that the `signer` specified",
-            "in the context equals an authorized pubkey specified in this account."
-          ]
-        },
         {
           "name": "peer",
           "writable": true,
@@ -1053,14 +1176,6 @@ export type TokenBridgeRelayer = {
         {
           "name": "chainConfig",
           "writable": true
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1073,7 +1188,12 @@ export type TokenBridgeRelayer = {
     {
       "name": "submitOwnerTransferRequest",
       "docs": [
-        "Updates the owner account. This needs to be either cancelled or approved."
+        "Updates the owner account. This needs to be either cancelled or approved.",
+        "",
+        "For safety reasons, transferring ownership is a 2-step process. This first step is to set the",
+        "new owner, and the second step is for the new owner to claim the ownership.",
+        "This is to prevent a situation where the ownership is transferred to an",
+        "address that is not able to claim the ownership (by mistake)."
       ],
       "discriminator": [
         99,
@@ -1116,6 +1236,116 @@ export type TokenBridgeRelayer = {
               }
             ]
           }
+        },
+        {
+          "name": "upgradeLock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "name": "programData",
+          "writable": true,
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  13,
+                  74,
+                  247,
+                  118,
+                  36,
+                  164,
+                  201,
+                  97,
+                  25,
+                  221,
+                  241,
+                  144,
+                  142,
+                  148,
+                  63,
+                  218,
+                  160,
+                  137,
+                  78,
+                  28,
+                  18,
+                  140,
+                  195,
+                  112,
+                  127,
+                  26,
+                  150,
+                  227,
+                  211,
+                  125,
+                  216,
+                  108
+                ]
+              }
+            ],
+            "program": {
+              "kind": "const",
+              "value": [
+                2,
+                168,
+                246,
+                145,
+                78,
+                136,
+                161,
+                176,
+                226,
+                16,
+                21,
+                62,
+                247,
+                99,
+                174,
+                43,
+                0,
+                194,
+                185,
+                61,
+                22,
+                193,
+                36,
+                210,
+                192,
+                83,
+                122,
+                16,
+                4,
+                128,
+                0,
+                0
+              ]
+            }
+          }
+        },
+        {
+          "name": "bpfLoaderUpgradeable",
+          "address": "BPFLoaderUpgradeab1e11111111111111111111111"
         }
       ],
       "args": [
@@ -1199,9 +1429,6 @@ export type TokenBridgeRelayer = {
         },
         {
           "name": "feeRecipient",
-          "docs": [
-            "Fee recipient's account. The fee will be transferred to this account."
-          ],
           "writable": true,
           "relations": [
             "tbrConfig"
@@ -1387,18 +1614,7 @@ export type TokenBridgeRelayer = {
           "docs": [
             "Owner of the program as set in the [`TbrConfig`] account."
           ],
-          "writable": true,
-          "signer": true,
-          "relations": [
-            "tbrConfig"
-          ]
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Owner Config account. This program requires that the `owner` specified",
-            "in the context equals the `owner` pubkey specified in this account."
-          ]
+          "signer": true
         },
         {
           "name": "peer"
@@ -1555,14 +1771,6 @@ export type TokenBridgeRelayer = {
         {
           "name": "chainConfig",
           "writable": true
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1610,14 +1818,6 @@ export type TokenBridgeRelayer = {
         {
           "name": "chainConfig",
           "writable": true
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1759,63 +1959,73 @@ export type TokenBridgeRelayer = {
     },
     {
       "code": 6007,
+      "name": "dropoffExceedingMaximum",
+      "msg": "dropoffExceedingMaximum"
+    },
+    {
+      "code": 6008,
       "name": "feeExceedingMaximum",
       "msg": "feeExceedingMaximum"
     },
     {
-      "code": 6008,
+      "code": 6009,
       "name": "wrongFeeRecipient",
       "msg": "wrongFeeRecipient"
     },
     {
-      "code": 6009,
+      "code": 6010,
       "name": "wronglySetOptionalAccounts",
       "msg": "wronglySetOptionalAccounts"
     },
     {
-      "code": 6010,
+      "code": 6011,
       "name": "wrongMintAuthority",
       "msg": "wrongMintAuthority"
     },
     {
-      "code": 6011,
+      "code": 6012,
       "name": "invalidRecipient",
       "msg": "invalidRecipient"
     },
     {
-      "code": 6012,
+      "code": 6013,
       "name": "evmChainPriceNotSet",
       "msg": "evmChainPriceNotSet"
     },
     {
-      "code": 6013,
+      "code": 6014,
       "name": "chainPriceMismatch",
       "msg": "chainPriceMismatch"
     },
     {
-      "code": 6014,
+      "code": 6015,
       "name": "pausedTransfers",
       "msg": "pausedTransfers"
     },
     {
-      "code": 6015,
+      "code": 6016,
       "name": "invalidSendingPeer",
       "msg": "invalidSendingPeer"
     },
     {
-      "code": 6016,
+      "code": 6017,
       "name": "cannotRegisterSolana",
       "msg": "cannotRegisterSolana"
     },
     {
-      "code": 6017,
+      "code": 6018,
       "name": "invalidPeerAddress",
       "msg": "invalidPeerAddress"
     },
     {
-      "code": 6018,
+      "code": 6019,
       "name": "missingAssociatedTokenAccount",
       "msg": "missingAssociatedTokenAccount"
+    },
+    {
+      "code": 6020,
+      "name": "overflow",
+      "msg": "overflow"
     }
   ],
   "types": [
@@ -2059,6 +2269,11 @@ export type TokenBridgeRelayer = {
       "name": "seedPrefixTemporary",
       "type": "bytes",
       "value": "[116, 109, 112]"
+    },
+    {
+      "name": "seedPrefixUpgradeLock",
+      "type": "bytes",
+      "value": "[117, 112, 103, 114, 97, 100, 101, 32, 108, 111, 99, 107]"
     }
   ]
 };
diff --git a/sdk/solana/tbrv3/token-bridge-relayer.ts b/sdk/solana/tbrv3/token-bridge-relayer.ts
index 7e9bb65c..612679eb 100644
--- a/sdk/solana/tbrv3/token-bridge-relayer.ts
+++ b/sdk/solana/tbrv3/token-bridge-relayer.ts
@@ -260,7 +260,7 @@ export class SolanaTokenBridgeRelayer {
           chain === undefined
             ? undefined
             : Buffer.from(
-                serializeLayout({ ...layoutItems.chainItem(), endianness: 'big' }, chain),
+                serializeLayout({ ...layoutItems.chainItem(), endianness: 'little' }, chain),
               );
         const states = await this.program.account.peerState
           .all(filter)
@@ -344,7 +344,7 @@ export class SolanaTokenBridgeRelayer {
           ]).address;
 
     const wallet = uaToPubkey(deserializeTbrV3Message(vaa.payload.payload).recipient);
-    const associatedTokenAccount = getAssociatedTokenAccount(wallet, mint);
+    const associatedTokenAccount = spl.getAssociatedTokenAddressSync(mint, wallet);
 
     return { wallet, associatedTokenAccount };
   }
@@ -410,7 +410,6 @@ export class SolanaTokenBridgeRelayer {
       .confirmOwnerTransferRequest()
       .accounts({
         newOwner: config.pendingOwner ?? throwError('No pending owner in the program'),
-        previousOwner: config.owner,
         tbrConfig: this.account.config().address,
       })
       .instruction();
@@ -424,7 +423,7 @@ export class SolanaTokenBridgeRelayer {
 
     return this.program.methods
       .cancelOwnerTransferRequest()
-      .accountsStrict({
+      .accountsPartial({
         owner: config.owner,
         tbrConfig: this.account.config().address,
       })
@@ -468,7 +467,50 @@ export class SolanaTokenBridgeRelayer {
   /**
    * Signer: the Owner or an Admin.
    */
-  async registerPeer(
+  async registerFirstPeer(
+    signer: PublicKey,
+    chain: Chain,
+    peerAddress: UniversalAddress,
+    config: {
+      maxGasDropoffMicroToken: number;
+      relayerFeeMicroUsd: number;
+      pausedOutboundTransfers: boolean;
+    },
+  ): Promise<TransactionInstruction[]> {
+    // Check if there are no existing peers:
+    const existingPeers = await this.read.allPeers(chain);
+    if (existingPeers.length > 0) {
+      throw new Error('Peers already exist. Use registerAdditionalPeer to add more peers.');
+    }
+
+    const updateMaxGasDropoffIx =
+      config.maxGasDropoffMicroToken !== 0
+        ? [this.updateMaxGasDropoff(signer, chain, config.maxGasDropoffMicroToken)]
+        : [];
+
+    return Promise.all([
+      this.registerPeer(signer, chain, peerAddress),
+      this.updateBaseFee(signer, chain, config.relayerFeeMicroUsd),
+      this.setPauseForOutboundTransfers(signer, chain, config.pausedOutboundTransfers),
+      ...updateMaxGasDropoffIx,
+    ]);
+  }
+
+  async registerAdditionalPeer(
+    signer: PublicKey,
+    chain: Chain,
+    peerAddress: UniversalAddress,
+  ): Promise<TransactionInstruction> {
+    // Check if there are no existing peers:
+    const existingPeers = await this.read.allPeers(chain);
+    if (existingPeers.length === 0) {
+      throw new Error('No peer for this chain. Use registerFirstPeer instead.');
+    }
+
+    return this.registerPeer(signer, chain, peerAddress);
+  }
+
+  private async registerPeer(
     signer: PublicKey,
     chain: Chain,
     peerAddress: UniversalAddress,
@@ -478,7 +520,6 @@ export class SolanaTokenBridgeRelayer {
       .accountsStrict({
         signer,
         authBadge: this.account.authBadge(signer).address,
-        tbrConfig: this.account.config().address,
         peer: this.account.peer(chain, peerAddress).address,
         chainConfig: this.account.chainConfig(chain).address,
         systemProgram: SystemProgram.programId,
@@ -499,7 +540,6 @@ export class SolanaTokenBridgeRelayer {
       .updateCanonicalPeer()
       .accountsStrict({
         owner: config.owner,
-        tbrConfig: this.account.config().address,
         peer: this.account.peer(chain, peerAddress).address,
         chainConfig: this.account.chainConfig(chain).address,
         systemProgram: SystemProgram.programId,
@@ -523,7 +563,6 @@ export class SolanaTokenBridgeRelayer {
         signer,
         authBadge: this.account.authBadge(signer).address,
         chainConfig: this.account.chainConfig(chain).address,
-        tbrConfig: this.account.config().address,
       })
       .instruction();
   }
@@ -542,15 +581,16 @@ export class SolanaTokenBridgeRelayer {
         signer,
         authBadge: this.account.authBadge(signer).address,
         chainConfig: this.account.chainConfig(chain).address,
-        tbrConfig: this.account.config().address,
       })
       .instruction();
   }
 
   /**
+   * Change the fee asked for relaying a transfer.
+   *
    * Signer: the Owner or an Admin.
    */
-  async updateRelayerFee(
+  async updateBaseFee(
     signer: PublicKey,
     chain: Chain,
     relayerFee: number,
@@ -561,7 +601,6 @@ export class SolanaTokenBridgeRelayer {
         signer,
         authBadge: this.account.authBadge(signer).address,
         chainConfig: this.account.chainConfig(chain).address,
-        tbrConfig: this.account.config().address,
       })
       .instruction();
   }
@@ -899,13 +938,6 @@ function findPda(programId: PublicKey, seeds: Array<string | Uint8Array>) {
   };
 }
 
-function getAssociatedTokenAccount(wallet: PublicKey, mint: PublicKey): PublicKey {
-  return PublicKey.findProgramAddressSync(
-    [wallet.toBuffer(), spl.TOKEN_PROGRAM_ID.toBuffer(), mint.toBuffer()],
-    spl.ASSOCIATED_TOKEN_PROGRAM_ID,
-  )[0];
-}
-
 /** Return both the address and an idempotent instruction to create it. */
 async function createAssociatedTokenAccountIdempotent({
   signer,
@@ -916,7 +948,7 @@ async function createAssociatedTokenAccountIdempotent({
   mint: PublicKey;
   wallet: PublicKey;
 }): Promise<TransactionInstruction> {
-  const recipientTokenAccount = getAssociatedTokenAccount(wallet, mint);
+  const recipientTokenAccount = spl.getAssociatedTokenAddressSync(mint, wallet);
 
   const createAtaIdempotentIx = spl.createAssociatedTokenAccountIdempotentInstruction(
     signer,
@@ -1018,6 +1050,13 @@ function range(from: bigint, to: bigint): bigint[] {
   return Array.from(generator(from, to));
 }
 
+/**
+ * Simulates the transaction and returns the result. Throws if it failed.
+ * @param connection The connection used to run the simulation.
+ * @param payer The payer. No signature is needed, so no fee will be payed.
+ * @param instructions The instructions to simulate.
+ * @returns
+ */
 async function simulateTransaction(
   connection: Connection,
   payer: PublicKey,
diff --git a/solana/programs/token-bridge-relayer/src/error.rs b/solana/programs/token-bridge-relayer/src/error.rs
index cc1676e5..823dffff 100644
--- a/solana/programs/token-bridge-relayer/src/error.rs
+++ b/solana/programs/token-bridge-relayer/src/error.rs
@@ -33,6 +33,10 @@ pub(crate) enum TokenBridgeRelayerError {
     #[msg("AlreadyTheCanonicalPeer")]
     AlreadyTheCanonicalPeer,
 
+    /// The dropoff amount it higher than the one authorized for the target chain.
+    #[msg("DropoffExceedingMaximum")]
+    DropoffExceedingMaximum,
+
     /// Fee exceed what the user has set as a maximum.
     #[msg("FeeExceedingMaximum")]
     FeeExceedingMaximum,
@@ -86,4 +90,8 @@ pub(crate) enum TokenBridgeRelayerError {
     /// unwrap intent is set to `true`.
     #[msg("MissingAssociatedTokenAccount")]
     MissingAssociatedTokenAccount,
+
+    /// Numerical overflow.
+    #[msg("Overflow")]
+    Overflow,
 }
diff --git a/solana/programs/token-bridge-relayer/src/lib.rs b/solana/programs/token-bridge-relayer/src/lib.rs
index 873a61f0..1b7ce340 100644
--- a/solana/programs/token-bridge-relayer/src/lib.rs
+++ b/solana/programs/token-bridge-relayer/src/lib.rs
@@ -18,6 +18,9 @@ pub mod constant {
 
     #[constant]
     pub const SEED_PREFIX_TEMPORARY: &[u8] = b"tmp";
+
+    #[constant]
+    pub const SEED_PREFIX_UPGRADE_LOCK: &[u8] = b"upgrade_lock";
 }
 
 #[program]
@@ -35,6 +38,11 @@ pub mod token_bridge_relayer {
     /* Roles */
 
     /// Updates the owner account. This needs to be either cancelled or approved.
+    ///
+    /// For safety reasons, transferring ownership is a 2-step process. This first step is to set the
+    /// new owner, and the second step is for the new owner to claim the ownership.
+    /// This is to prevent a situation where the ownership is transferred to an
+    /// address that is not able to claim the ownership (by mistake).
     pub fn submit_owner_transfer_request(
         ctx: Context<SubmitOwnerTransfer>,
         new_owner: Pubkey,
diff --git a/solana/programs/token-bridge-relayer/src/processor/chain_config.rs b/solana/programs/token-bridge-relayer/src/processor/chain_config.rs
index 20467bf0..7eb917a7 100644
--- a/solana/programs/token-bridge-relayer/src/processor/chain_config.rs
+++ b/solana/programs/token-bridge-relayer/src/processor/chain_config.rs
@@ -1,6 +1,6 @@
 use crate::{
     error::TokenBridgeRelayerError,
-    state::{AuthBadgeState, ChainConfigState, TbrConfigState},
+    state::{AuthBadgeState, ChainConfigState},
 };
 use anchor_lang::prelude::*;
 
@@ -16,11 +16,6 @@ pub struct UpdateChainConfig<'info> {
 
     #[account(mut)]
     pub chain_config: Account<'info, ChainConfigState>,
-
-    /// Program Config account. This program requires that the [`signer`] specified
-    /// in the context equals a pubkey specified in this account. Mutable,
-    /// because we will update roles depending on the operation.
-    pub tbr_config: Account<'info, TbrConfigState>,
 }
 
 pub fn set_pause_for_outbound_transfers(
diff --git a/solana/programs/token-bridge-relayer/src/processor/inbound.rs b/solana/programs/token-bridge-relayer/src/processor/inbound.rs
index 498799a2..881a4dcd 100644
--- a/solana/programs/token-bridge-relayer/src/processor/inbound.rs
+++ b/solana/programs/token-bridge-relayer/src/processor/inbound.rs
@@ -23,7 +23,7 @@ pub struct CompleteTransfer<'info> {
     pub tbr_config: Box<Account<'info, TbrConfigState>>,
 
     /// Mint info. This is the SPL token that will be bridged over to the
-    /// foreign contract. Mutable.
+    /// foreign contract.
     ///
     /// In the case of a native transfer, it's the mint for the token wrapped by Wormhole;
     /// in the case of a wrapped transfer, it's the native SPL token mint.
@@ -32,7 +32,7 @@ pub struct CompleteTransfer<'info> {
 
     /// Recipient associated token account. The recipient authority check
     /// is necessary to ensure that the recipient is the intended recipient
-    /// of the bridged tokens. Mutable.
+    /// of the bridged tokens.
     #[account(
         mut,
         associated_token::mint = mint,
@@ -44,7 +44,7 @@ pub struct CompleteTransfer<'info> {
     /// transaction. This instruction verifies that the recipient key
     /// passed in this context matches the intended recipient in the vaa.
     #[account(mut)]
-    pub recipient: AccountInfo<'info>,
+    pub recipient: UncheckedAccount<'info>,
 
     /// Verified Wormhole message account. Read-only.
     pub vaa: Account<'info, PostedRelayerMessage>,
@@ -61,10 +61,10 @@ pub struct CompleteTransfer<'info> {
     #[account(mut)]
     pub temporary_account: UncheckedAccount<'info>,
 
+    /// The TBR peer (_i.e._ `data().from_address()`). We do not care about the Token Bridge peer `vaa.meta.emitter_address`.
     #[account(
-        constraint = {
-            peer.address == *vaa.data().from_address()
-        } @ TokenBridgeRelayerError::InvalidSendingPeer
+        constraint = peer.address == *vaa.data().from_address() && peer.chain_id == vaa.meta.emitter_chain
+            @ TokenBridgeRelayerError::InvalidSendingPeer
     )]
     pub peer: Account<'info, PeerState>,
 
@@ -89,7 +89,7 @@ pub struct CompleteTransfer<'info> {
     /// CHECK: Token Bridge custody. This is the Token Bridge program's token
     /// account that holds this mint's balance. This account needs to be
     /// unchecked because a token account may not have been created for this
-    /// mint yet. Mutable.
+    /// mint yet.
     ///
     /// # Exclusive
     ///
diff --git a/solana/programs/token-bridge-relayer/src/processor/initialize.rs b/solana/programs/token-bridge-relayer/src/processor/initialize.rs
index d222543a..e4160491 100644
--- a/solana/programs/token-bridge-relayer/src/processor/initialize.rs
+++ b/solana/programs/token-bridge-relayer/src/processor/initialize.rs
@@ -1,6 +1,7 @@
 use crate::{
     error::TokenBridgeRelayerError,
     state::{AuthBadgeState, TbrConfigState},
+    utils::DrainAccount,
 };
 use anchor_lang::prelude::*;
 use anchor_lang::solana_program::{bpf_loader_upgradeable, program::invoke};
@@ -15,7 +16,7 @@ pub struct Initialize<'info> {
     #[account(mut)]
     pub deployer: Signer<'info>,
 
-    /// The designated owner of the program.
+    /// CHECK: The account to be used as the owner of the program.
     pub owner: UncheckedAccount<'info>,
 
     #[account(
@@ -28,7 +29,7 @@ pub struct Initialize<'info> {
     pub auth_badge: Account<'info, AuthBadgeState>,
 
     /// Owner Config account. This program requires that the `owner` specified
-    /// in the context equals the pubkey specified in this account. Mutable.
+    /// in the context equals the pubkey specified in this account.
     #[account(
         init,
         payer = deployer,
@@ -46,18 +47,21 @@ pub struct Initialize<'info> {
     )]
     program_data: Account<'info, ProgramData>,
 
+    /// CHECK: An account used by the Token Bridge.
     #[account(
         seeds = [token_bridge::SEED_PREFIX_SENDER],
         bump
     )]
     pub wormhole_sender: UncheckedAccount<'info>,
 
+    /// CHECK: An account used by the Token Bridge.
     #[account(
         seeds = [token_bridge::SEED_PREFIX_REDEEMER],
         bump
     )]
     pub wormhole_redeemer: UncheckedAccount<'info>,
 
+    /// CHECK: The BPF loader program.
     #[account(address = bpf_loader_upgradeable::ID)]
     pub bpf_loader_upgradeable: UncheckedAccount<'info>,
 
@@ -114,11 +118,20 @@ pub fn initialize<'a, 'b, 'c, 'info>(
     );
 
     for (admin, badge_acc_info) in zip(admins, ctx.remaining_accounts) {
-        let bump = Pubkey::find_program_address(
+        let (_pubkey, bump) = Pubkey::find_program_address(
             &[AuthBadgeState::SEED_PREFIX, admin.to_bytes().as_ref()],
             ctx.program_id,
-        )
-        .1;
+        );
+        let badge_seeds = [AuthBadgeState::SEED_PREFIX, &admin.to_bytes(), &[bump]];
+
+        // Before calling `create_account`, we need to verify that the account
+        // has an empty balance, otherwise the instruction would fail:
+        DrainAccount {
+            system_program: ctx.accounts.system_program.to_account_info(),
+            account: badge_acc_info.to_account_info(),
+            recipient: ctx.accounts.deployer.to_account_info(),
+        }
+        .run_with_seeds(&badge_seeds)?;
 
         anchor_lang::system_program::create_account(
             CpiContext::new_with_signer(
@@ -127,11 +140,7 @@ pub fn initialize<'a, 'b, 'c, 'info>(
                     from: ctx.accounts.deployer.to_account_info(),
                     to: badge_acc_info.clone(),
                 },
-                &[&[
-                    AuthBadgeState::SEED_PREFIX,
-                    admin.to_bytes().as_ref(),
-                    &[bump],
-                ]],
+                &[&badge_seeds],
             ),
             Rent::get()?.minimum_balance(8 + AuthBadgeState::INIT_SPACE),
             (8 + AuthBadgeState::INIT_SPACE) as u64,
diff --git a/solana/programs/token-bridge-relayer/src/processor/outbound.rs b/solana/programs/token-bridge-relayer/src/processor/outbound.rs
index aeef23a6..0fc64532 100644
--- a/solana/programs/token-bridge-relayer/src/processor/outbound.rs
+++ b/solana/programs/token-bridge-relayer/src/processor/outbound.rs
@@ -36,7 +36,7 @@ pub struct OutboundTransfer<'info> {
     pub chain_config: Box<Account<'info, ChainConfigState>>,
 
     /// Mint info. This is the SPL token that will be bridged over to the
-    /// canonical peer. Mutable.
+    /// canonical peer.
     ///
     /// In the case of a native transfer, it's the native mint; in the case of a
     /// wrapped transfer, it's the token wrapped by Wormhole.
@@ -62,7 +62,7 @@ pub struct OutboundTransfer<'info> {
     #[account(mut)]
     pub temporary_account: UncheckedAccount<'info>,
 
-    /// Fee recipient's account. The fee will be transferred to this account.
+    /// CHECK: Fee recipient's account. The fee will be transferred to this account.
     #[account(mut)]
     pub fee_recipient: UncheckedAccount<'info>,
 
@@ -80,7 +80,7 @@ pub struct OutboundTransfer<'info> {
     /// CHECK: Token Bridge custody. This is the Token Bridge program's token
     /// account that holds this mint's balance. This account needs to be
     /// unchecked because a token account may not have been created for this
-    /// mint yet. Mutable.
+    /// mint yet.
     ///
     /// # Exclusive
     ///
@@ -116,7 +116,7 @@ pub struct OutboundTransfer<'info> {
     /// CHECK: Token Bridge emitter.
     pub token_bridge_emitter: UncheckedAccount<'info>,
 
-    /// CHECK: Token Bridge sequence.
+    /// CHECK: Token Bridge sequence. Mutable.
     #[account(mut)]
     pub token_bridge_sequence: UncheckedAccount<'info>,
 
@@ -131,8 +131,9 @@ pub struct OutboundTransfer<'info> {
         ],
         bump,
     )]
-    pub wormhole_message: AccountInfo<'info>,
+    pub wormhole_message: UncheckedAccount<'info>,
 
+    /// CHECK: Wormhole sender.
     pub wormhole_sender: UncheckedAccount<'info>,
 
     /// CHECK: Wormhole fee collector. Mutable.
@@ -184,6 +185,11 @@ pub fn transfer_tokens(
         &[ctx.accounts.tbr_config.sender_bump],
     ];
 
+    require!(
+        dropoff_amount_micro <= ctx.accounts.chain_config.max_gas_dropoff_micro_token,
+        TokenBridgeRelayerError::DropoffExceedingMaximum
+    );
+
     let transferred_amount = normalize_token_amount(transferred_amount, &ctx.accounts.mint);
     let total_fees_lamports = calculate_total_fee(
         &ctx.accounts.tbr_config,
diff --git a/solana/programs/token-bridge-relayer/src/processor/owner.rs b/solana/programs/token-bridge-relayer/src/processor/owner.rs
index a41fbb39..be134705 100644
--- a/solana/programs/token-bridge-relayer/src/processor/owner.rs
+++ b/solana/programs/token-bridge-relayer/src/processor/owner.rs
@@ -1,12 +1,13 @@
 //! Everything about the owner or admin role transfer.
 
 use crate::{
+    constant::SEED_PREFIX_UPGRADE_LOCK,
     error::TokenBridgeRelayerError,
     state::{AuthBadgeState, TbrConfigState},
 };
 use anchor_lang::{
     prelude::*,
-    solana_program::{bpf_loader_upgradeable, program::invoke},
+    solana_program::{bpf_loader_upgradeable, program::invoke_signed},
 };
 
 #[derive(Accounts)]
@@ -23,6 +24,25 @@ pub struct SubmitOwnerTransfer<'info> {
         bump = tbr_config.bump
     )]
     pub tbr_config: Account<'info, TbrConfigState>,
+
+    /// CHECK: The seeds constraint enforces that this is the correct address
+    #[account(
+        seeds = [SEED_PREFIX_UPGRADE_LOCK],
+        bump,
+    )]
+    upgrade_lock: UncheckedAccount<'info>,
+
+    #[account(
+        mut,
+        seeds = [crate::ID.as_ref()],
+        bump,
+        seeds::program = bpf_loader_upgradeable::ID,
+    )]
+    program_data: Account<'info, ProgramData>,
+
+    /// CHECK: The BPF loader program.
+    #[account(address = bpf_loader_upgradeable::ID)]
+    pub bpf_loader_upgradeable: UncheckedAccount<'info>,
 }
 
 pub fn submit_owner_transfer_request(
@@ -38,6 +58,22 @@ pub fn submit_owner_transfer_request(
 
     ctx.accounts.tbr_config.pending_owner = Some(new_owner);
 
+    // Change the program authority to the upgrade lock PDA, so that the owner does not need
+    // to sign the transaction when confirming the ownership transfer:
+    invoke_signed(
+        &bpf_loader_upgradeable::set_upgrade_authority_checked(
+            &ctx.program_id,
+            &ctx.accounts.owner.key(),
+            &ctx.accounts.upgrade_lock.key(),
+        ),
+        &[
+            ctx.accounts.program_data.to_account_info(),
+            ctx.accounts.owner.to_account_info(),
+            ctx.accounts.upgrade_lock.to_account_info(),
+        ],
+        &[&[SEED_PREFIX_UPGRADE_LOCK, &[ctx.bumps.upgrade_lock]]],
+    )?;
+
     Ok(())
 }
 
@@ -46,8 +82,9 @@ pub struct ConfirmOwnerTransfer<'info> {
     #[account(mut)]
     pub new_owner: Signer<'info>,
 
+    /// CHECK: init_if_needed: If the new owner has already a badge, _i.e._ is an admin, we can reuse it. 
     #[account(
-        init,
+        init_if_needed,
         payer = new_owner,
         space = 8 + AuthBadgeState::INIT_SPACE,
         seeds = [AuthBadgeState::SEED_PREFIX, new_owner.key.to_bytes().as_ref()],
@@ -55,8 +92,6 @@ pub struct ConfirmOwnerTransfer<'info> {
     )]
     pub auth_badge_new_owner: Account<'info, AuthBadgeState>,
 
-    pub previous_owner: Signer<'info>,
-
     #[account(
         mut,
         seeds = [AuthBadgeState::SEED_PREFIX, tbr_config.owner.to_bytes().as_ref()],
@@ -75,6 +110,13 @@ pub struct ConfirmOwnerTransfer<'info> {
     )]
     pub tbr_config: Account<'info, TbrConfigState>,
 
+    /// CHECK: The seeds constraint enforces that this is the correct address
+    #[account(
+        seeds = [SEED_PREFIX_UPGRADE_LOCK],
+        bump,
+    )]
+    upgrade_lock: UncheckedAccount<'info>,
+
     #[account(
         mut,
         seeds = [crate::ID.as_ref()],
@@ -83,6 +125,7 @@ pub struct ConfirmOwnerTransfer<'info> {
     )]
     program_data: Account<'info, ProgramData>,
 
+    /// CHECK: The BPF loader program.
     #[account(address = bpf_loader_upgradeable::ID)]
     pub bpf_loader_upgradeable: UncheckedAccount<'info>,
 
@@ -93,17 +136,18 @@ pub fn confirm_owner_transfer_request(ctx: Context<ConfirmOwnerTransfer>) -> Res
     let tbr_config = &mut ctx.accounts.tbr_config;
 
     // Change the program authority to the new owner:
-    invoke(
+    invoke_signed(
         &bpf_loader_upgradeable::set_upgrade_authority(
             &ctx.program_id,
-            &ctx.accounts.previous_owner.key(),
+            &ctx.accounts.upgrade_lock.key(),
             Some(&ctx.accounts.new_owner.key()),
         ),
         &[
             ctx.accounts.program_data.to_account_info(),
-            ctx.accounts.previous_owner.to_account_info(),
+            ctx.accounts.upgrade_lock.to_account_info(),
             ctx.accounts.new_owner.to_account_info(),
         ],
+        &[&[SEED_PREFIX_UPGRADE_LOCK, &[ctx.bumps.upgrade_lock]]],
     )?;
 
     tbr_config.owner = ctx.accounts.new_owner.key();
@@ -128,10 +172,44 @@ pub struct CancelOwnerTransfer<'info> {
         has_one = owner @ TokenBridgeRelayerError::OwnerOnly,
     )]
     pub tbr_config: Account<'info, TbrConfigState>,
+
+    /// CHECK: The seeds constraint enforces that this is the correct address
+    #[account(
+        seeds = [SEED_PREFIX_UPGRADE_LOCK],
+        bump,
+    )]
+    upgrade_lock: UncheckedAccount<'info>,
+
+    #[account(
+        mut,
+        seeds = [crate::ID.as_ref()],
+        bump,
+        seeds::program = bpf_loader_upgradeable::ID,
+    )]
+    program_data: Account<'info, ProgramData>,
+
+    /// CHECK: The BPF loader program.
+    #[account(address = bpf_loader_upgradeable::ID)]
+    pub bpf_loader_upgradeable: UncheckedAccount<'info>,
 }
 
 pub fn cancel_owner_transfer_request(ctx: Context<CancelOwnerTransfer>) -> Result<()> {
     ctx.accounts.tbr_config.pending_owner = None;
 
+    // Transfer the program authority back to the owner:
+    invoke_signed(
+        &bpf_loader_upgradeable::set_upgrade_authority(
+            &ctx.program_id,
+            &ctx.accounts.upgrade_lock.key(),
+            Some(&ctx.accounts.owner.key()),
+        ),
+        &[
+            ctx.accounts.program_data.to_account_info(),
+            ctx.accounts.upgrade_lock.to_account_info(),
+            ctx.accounts.owner.to_account_info(),
+        ],
+        &[&[SEED_PREFIX_UPGRADE_LOCK, &[ctx.bumps.upgrade_lock]]],
+    )?;
+
     Ok(())
 }
diff --git a/solana/programs/token-bridge-relayer/src/processor/peers.rs b/solana/programs/token-bridge-relayer/src/processor/peers.rs
index 07d17bd4..cdc7253e 100644
--- a/solana/programs/token-bridge-relayer/src/processor/peers.rs
+++ b/solana/programs/token-bridge-relayer/src/processor/peers.rs
@@ -1,6 +1,6 @@
 use crate::{
     error::TokenBridgeRelayerError,
-    state::{AuthBadgeState, ChainConfigState, PeerState, TbrConfigState},
+    state::{AuthBadgeState, ChainConfigState, PeerState},
 };
 use anchor_lang::prelude::*;
 
@@ -18,10 +18,6 @@ pub struct RegisterPeer<'info> {
     #[account(constraint = &auth_badge.address == signer.key @ TokenBridgeRelayerError::OwnerOrAdminOnly)]
     pub auth_badge: Account<'info, AuthBadgeState>,
 
-    /// Owner Config account. This program requires that the `signer` specified
-    /// in the context equals an authorized pubkey specified in this account.
-    pub tbr_config: Account<'info, TbrConfigState>,
-
     #[account(
         init,
         payer = signer,
@@ -82,14 +78,8 @@ pub fn register_peer(
 #[derive(Accounts)]
 pub struct UpdateCanonicalPeer<'info> {
     /// Owner of the program as set in the [`TbrConfig`] account.
-    #[account(mut)]
     pub owner: Signer<'info>,
 
-    /// Owner Config account. This program requires that the `owner` specified
-    /// in the context equals the `owner` pubkey specified in this account.
-    #[account(has_one = owner @ TokenBridgeRelayerError::OwnerOnly)]
-    pub tbr_config: Account<'info, TbrConfigState>,
-
     #[account(
         constraint = {
             peer.chain_id == chain_config.chain_id
diff --git a/solana/programs/token-bridge-relayer/src/utils.rs b/solana/programs/token-bridge-relayer/src/utils.rs
index 1a78da8b..5e10d929 100644
--- a/solana/programs/token-bridge-relayer/src/utils.rs
+++ b/solana/programs/token-bridge-relayer/src/utils.rs
@@ -57,19 +57,36 @@ pub fn calculate_total_fee(
     */
 
     // Mwei = gas * Mwei/gas + bytes * Mwei/byte + µToken * Mwei/µToken
-    let total_fees_mwei = config.evm_transaction_gas * u64::from(oracle_evm_prices.gas_price)
-        + config.evm_transaction_size * u64::from(oracle_evm_prices.price_per_byte)
-        + u64::from(dropoff_amount_micro) * MWEI_PER_MICRO_ETH;
+    let total_fees_mwei = (|| {
+        let evm_transaction_fee_mwei = config
+            .evm_transaction_gas
+            .checked_mul(u64::from(oracle_evm_prices.gas_price))?;
+        let evm_tx_size_fee_mwei = config
+            .evm_transaction_size
+            .checked_mul(u64::from(oracle_evm_prices.price_per_byte))?;
+        let dropoff_mwei = u64::from(dropoff_amount_micro).checked_mul(MWEI_PER_MICRO_ETH)?;
+
+        evm_transaction_fee_mwei
+            .checked_add(evm_tx_size_fee_mwei)?
+            .checked_add(dropoff_mwei)
+    })()
+    .ok_or(TokenBridgeRelayerError::Overflow)?;
 
     // μusd = Mwei * μusd/Token / Mwei/Token + μusd)
     let total_fees_micro_usd = u64::try_from(
         u128::from(total_fees_mwei) * u128::from(oracle_evm_prices.gas_token_price) / MWEI_PER_ETH,
     )
-    .expect("Overflow")
-        + u64::from(chain_config.relayer_fee_micro_usd);
+    .map_err(|_| TokenBridgeRelayerError::Overflow)?
+    .checked_add(u64::from(chain_config.relayer_fee_micro_usd))
+    .ok_or(TokenBridgeRelayerError::Overflow)?;
 
     // lamports/SOL * μusd / μusd/SOL
-    Ok((LAMPORTS_PER_SOL * total_fees_micro_usd) / oracle_config.sol_price)
+    let fee = total_fees_micro_usd
+        .checked_mul(LAMPORTS_PER_SOL)
+        .map(|sol| sol / oracle_config.sol_price)
+        .ok_or(TokenBridgeRelayerError::Overflow)?;
+
+    Ok(fee)
 }
 
 /// This is a basic security against a wrong manip, to be sure that the prices
@@ -156,6 +173,15 @@ impl<'info> CreateAndInitTokenAccount<'info> {
     pub fn run_with_seeds(self, seeds: &[&[u8]]) -> Result<()> {
         const LEN: usize = anchor_spl::token::TokenAccount::LEN;
 
+        // Before calling `create_account`, we need to verify that the account
+        // has an empty balance, otherwise the instruction would fail:
+        DrainAccount {
+            system_program: self.system_program.clone(),
+            account: self.account.clone(),
+            recipient: self.payer.clone(),
+        }
+        .run_with_seeds(seeds)?;
+
         system_program::create_account(
             CpiContext::new_with_signer(
                 self.system_program,
@@ -184,3 +210,30 @@ impl<'info> CreateAndInitTokenAccount<'info> {
         Ok(())
     }
 }
+
+/// Empties the account balance to the provided recipient.
+pub struct DrainAccount<'info> {
+    pub system_program: AccountInfo<'info>,
+    pub account: AccountInfo<'info>,
+    pub recipient: AccountInfo<'info>,
+}
+
+impl<'info> DrainAccount<'info> {
+    pub fn run_with_seeds(self, seeds: &[&[u8]]) -> Result<()> {
+        if self.account.lamports() != 0 {
+            anchor_lang::system_program::transfer(
+                CpiContext::new_with_signer(
+                    self.system_program.to_account_info(),
+                    anchor_lang::system_program::Transfer {
+                        from: self.account.clone(),
+                        to: self.recipient,
+                    },
+                    &[seeds],
+                ),
+                self.account.lamports(),
+            )?;
+        }
+
+        Ok(())
+    }
+}
diff --git a/solana/tests/token-bridge-relayer-tests.ts b/solana/tests/token-bridge-relayer-tests.ts
index c97d9de7..d1383766 100644
--- a/solana/tests/token-bridge-relayer-tests.ts
+++ b/solana/tests/token-bridge-relayer-tests.ts
@@ -1,6 +1,12 @@
 import { chainToChainId } from '@wormhole-foundation/sdk-base';
 import { toNative, UniversalAddress } from '@wormhole-foundation/sdk-definitions';
-import { Keypair, PublicKey, SendTransactionError, Transaction } from '@solana/web3.js';
+import {
+  Keypair,
+  LAMPORTS_PER_SOL,
+  PublicKey,
+  SendTransactionError,
+  Transaction,
+} from '@solana/web3.js';
 import * as spl from '@solana/spl-token';
 import {
   assert,
@@ -34,6 +40,9 @@ const authorityKeypair = './target/deploy/token_bridge_relayer-keypair.json';
 
 const $ = new TestsHelper();
 
+/** SOL amount in lamports */ const sol = (n: number) => BigInt(LAMPORTS_PER_SOL * n);
+/** ETH amount in micro-ETH */ const eth = (n: number) => 1_000_000 * n;
+/** USD amount in micro-USD */ const usd = (n: number) => 1_000_000 * n;
 const uaToPubkey = (address: UniversalAddress) => toNative('Solana', address).unwrap();
 
 describe('Token Bridge Relayer Program', () => {
@@ -78,7 +87,11 @@ describe('Token Bridge Relayer Program', () => {
   const ethereumTbrPeer1 = $.universalAddress.generate('ethereum');
   const ethereumTbrPeer2 = $.universalAddress.generate('ethereum');
   const oasisTbrPeer = $.universalAddress.generate('ethereum');
-  const bpfProgram = new BpfLoaderUpgradeableProgram(ownerClient.client.program.programId, $.connection);
+
+  const bpfProgram = new BpfLoaderUpgradeableProgram(
+    ownerClient.client.program.programId,
+    $.connection,
+  );
 
   before(async () => {
     await $.airdrop([
@@ -144,6 +157,9 @@ describe('Token Bridge Relayer Program', () => {
       DEBUG,
     );
 
+    // Let's credit a badge, to verify that we cannot trigger a denial of service:
+    await $.airdrop(upgradeAuthorityClient.account.authBadge(adminClient1.publicKey).address);
+
     await upgradeAuthorityClient.initialize({
       feeRecipient,
       owner: ownerClient.publicKey,
@@ -184,12 +200,12 @@ describe('Token Bridge Relayer Program', () => {
 
     it('Rejects a transfer validation by an unauthorized account', async () => {
       await assert
-        .promise(unauthorizedClient.confirmOwnerTransferRequest(ownerClient.signer))
+        .promise(unauthorizedClient.confirmOwnerTransferRequest())
         .failsWith('Signature verification failed');
     });
 
     it('Accepts a transfer validation by the rightful new owner', async () => {
-      await newOwnerClient.confirmOwnerTransferRequest(ownerClient.signer);
+      await newOwnerClient.confirmOwnerTransferRequest();
 
       // Verify that the authority has been updated to the new owner.
       const { upgradeAuthority } = await bpfProgram.getdata();
@@ -215,7 +231,7 @@ describe('Token Bridge Relayer Program', () => {
 
       // Now the original owner cannot accept the ownership:
       await assert
-        .promise(ownerClient.confirmOwnerTransferRequest(ownerClient.signer))
+        .promise(ownerClient.confirmOwnerTransferRequest())
         .failsWith('No pending owner in the program');
     });
 
@@ -274,13 +290,22 @@ describe('Token Bridge Relayer Program', () => {
 
   describe('Peers', () => {
     it('Registers peers', async () => {
-      await newOwnerClient.registerPeer(ETHEREUM, ethereumTbrPeer1);
+      // First ETH peer:
+
+      await assert
+        .promise(newOwnerClient.registerAdditionalPeer(ETHEREUM, ethereumTbrPeer1))
+        .failsWith('Use registerFirstPeer instead');
+
+      const ethConfig = {
+        maxGasDropoffMicroToken: 1000,
+        pausedOutboundTransfers: false,
+        relayerFeeMicroUsd: 200,
+      };
+      await newOwnerClient.registerFirstPeer(ETHEREUM, ethereumTbrPeer1, ethConfig);
       assert.chainConfig(await unauthorizedClient.account.chainConfig(ETHEREUM).fetch()).equal({
         chainId: ETHEREUM_ID,
         canonicalPeer: uaToArray(ethereumTbrPeer1),
-        maxGasDropoffMicroToken: 0,
-        pausedOutboundTransfers: true,
-        relayerFeeMicroUsd: 0,
+        ...ethConfig,
       });
       expect(
         await unauthorizedClient.account.peer(ETHEREUM, ethereumTbrPeer1).fetch(),
@@ -289,13 +314,17 @@ describe('Token Bridge Relayer Program', () => {
         address: uaToArray(ethereumTbrPeer1),
       });
 
-      await adminClient1.registerPeer(ETHEREUM, ethereumTbrPeer2);
+      // Second ETH peer:
+
+      await assert
+        .promise(newOwnerClient.registerFirstPeer(ETHEREUM, ethereumTbrPeer2, ethConfig))
+        .failsWith('Peers already exist');
+
+      await adminClient1.registerAdditionalPeer(ETHEREUM, ethereumTbrPeer2);
       assert.chainConfig(await unauthorizedClient.account.chainConfig(ETHEREUM).fetch()).equal({
         chainId: ETHEREUM_ID,
         canonicalPeer: uaToArray(ethereumTbrPeer1),
-        maxGasDropoffMicroToken: 0,
-        pausedOutboundTransfers: true,
-        relayerFeeMicroUsd: 0,
+        ...ethConfig,
       });
       expect(
         await unauthorizedClient.account.peer(ETHEREUM, ethereumTbrPeer2).fetch(),
@@ -304,20 +333,23 @@ describe('Token Bridge Relayer Program', () => {
         address: uaToArray(ethereumTbrPeer2),
       });
 
-      await adminClient1.registerPeer(OASIS, oasisTbrPeer);
+      // First OASIS peer:
+
+      const oasisConfig = {
+        maxGasDropoffMicroToken: 650,
+        pausedOutboundTransfers: true,
+        relayerFeeMicroUsd: 430,
+      };
+      await adminClient1.registerFirstPeer(OASIS, oasisTbrPeer, oasisConfig);
       assert.chainConfig(await unauthorizedClient.account.chainConfig(OASIS).fetch()).equal({
         chainId: OASIS_ID,
         canonicalPeer: uaToArray(oasisTbrPeer),
-        maxGasDropoffMicroToken: 0,
-        pausedOutboundTransfers: true,
-        relayerFeeMicroUsd: 0,
+        ...oasisConfig,
       });
       assert.chainConfig(await unauthorizedClient.account.chainConfig(ETHEREUM).fetch()).equal({
         chainId: ETHEREUM_ID,
         canonicalPeer: uaToArray(ethereumTbrPeer1),
-        maxGasDropoffMicroToken: 0,
-        pausedOutboundTransfers: true,
-        relayerFeeMicroUsd: 0,
+        ...ethConfig,
       });
       expect(await unauthorizedClient.account.peer(OASIS, oasisTbrPeer).fetch()).deep.include({
         chainId: OASIS_ID,
@@ -331,9 +363,9 @@ describe('Token Bridge Relayer Program', () => {
       assert.chainConfig(await unauthorizedClient.account.chainConfig(ETHEREUM).fetch()).equal({
         chainId: ETHEREUM_ID,
         canonicalPeer: uaToArray(ethereumTbrPeer2),
-        maxGasDropoffMicroToken: 0,
-        pausedOutboundTransfers: true,
-        relayerFeeMicroUsd: 0,
+        maxGasDropoffMicroToken: 1000,
+        pausedOutboundTransfers: false,
+        relayerFeeMicroUsd: 200,
       });
     });
 
@@ -352,7 +384,7 @@ describe('Token Bridge Relayer Program', () => {
     it('Does not let unauthorized signers register or update a peer', async () => {
       // Unauthorized cannot register a peer:
       await assert
-        .promise(unauthorizedClient.registerPeer(ETHEREUM, $.universalAddress.generate()))
+        .promise(unauthorizedClient.registerAdditionalPeer(ETHEREUM, $.universalAddress.generate()))
         .failsWith('AnchorError caused by account: auth_badge. Error Code: AccountNotInitialized.');
 
       // Admin cannot make another peer canonical:
@@ -364,8 +396,8 @@ describe('Token Bridge Relayer Program', () => {
 
   describe('Chain Config', () => {
     it('Values are updated', async () => {
-      const maxGasDropoffMicroToken = 10_000_000; // ETH10 maximum
-      const relayerFeeMicroUsd = 900_000; // $0.9
+      const maxGasDropoffMicroToken = eth(10);
+      const relayerFeeMicroUsd = usd(0.9);
       await Promise.all([
         adminClient1.setPauseForOutboundTransfers(ETHEREUM, false),
         adminClient1.updateMaxGasDropoff(ETHEREUM, maxGasDropoffMicroToken),
@@ -420,7 +452,7 @@ describe('Token Bridge Relayer Program', () => {
 
   describe('Querying the relaying fee', () => {
     it('No discrepancy between SDK and program calculation', async () => {
-      const dropoff = 50000; // ETH0.05
+      const dropoff = eth(0.05);
 
       const simulatedResult = await unauthorizedClient.relayingFeeSimulated(ETHEREUM, dropoff);
       const offChainResult = await unauthorizedClient.relayingFee(ETHEREUM, dropoff);
@@ -458,12 +490,15 @@ describe('Token Bridge Relayer Program', () => {
       const foreignAddress = $.universalAddress.generate();
       const canonicalEthereum = await unauthorizedClient.read.canonicalPeer(ETHEREUM);
 
+      // Let's credit the temporary token account, to verify that we cannot trigger a denial of service:
+      await $.airdrop(unauthorizedClient.account.temporary(spl.NATIVE_MINT).address);
+
       await unauthorizedClient.transferTokens({
         recipient: { address: foreignAddress, chain: ETHEREUM },
         userTokenAccount: tokenAccount.publicKey,
         transferredAmount,
         gasDropoffAmount,
-        maxFeeLamports: 100_000_000n, // 0.1SOL max
+        maxFeeLamports: sol(0.1),
         unwrapIntent,
         mintAddress: spl.NATIVE_MINT,
       });
@@ -485,7 +520,6 @@ describe('Token Bridge Relayer Program', () => {
       expect(vaa.payload.token.amount).equal(transferredAmount / 10n);
 
       expect(vaa.payload.payload.recipient).deep.equal(foreignAddress);
-      // We need to divide by 1 million because it's deserialized as the token, not µToken:
       expect(vaa.payload.payload.gasDropoff).equal(gasDropoffAmount);
       expect(vaa.payload.payload.unwrapIntent).equal(unwrapIntent);
     });
@@ -495,7 +529,7 @@ describe('Token Bridge Relayer Program', () => {
       const unwrapIntent = false; // Does not matter anyway
       const transferredAmount = 321654n;
 
-      const tokenAccount = await barMint.mint(1_000_000_000n, unauthorizedClient.signer); //
+      const tokenAccount = await barMint.mint(1_000_000_000n, unauthorizedClient.signer);
 
       const foreignAddress = $.universalAddress.generate();
       const canonicalEthereum = await unauthorizedClient.read.canonicalPeer(ETHEREUM);
@@ -505,7 +539,7 @@ describe('Token Bridge Relayer Program', () => {
         userTokenAccount: tokenAccount.publicKey,
         transferredAmount,
         gasDropoffAmount,
-        maxFeeLamports: 100_000_000n, // 0.1SOL max
+        maxFeeLamports: sol(0.1),
         unwrapIntent,
         mintAddress: barMint.address,
       });
@@ -526,13 +560,12 @@ describe('Token Bridge Relayer Program', () => {
       expect(vaa.payload.token.amount).equal(transferredAmount / 100n);
 
       expect(vaa.payload.payload.recipient).deep.equal(foreignAddress);
-      // We need to divide by 1 million because it's deserialize as the token, not µToken:
-      expect(vaa.payload.payload.gasDropoff).equal(gasDropoffAmount / 1_000_000);
+      expect(vaa.payload.payload.gasDropoff).equal(gasDropoffAmount);
       expect(vaa.payload.payload.unwrapIntent).equal(unwrapIntent);
     });
 
     it('Gets wrapped SOL back from another chain', async () => {
-      const [payer, recipient] = await $.airdrop([Keypair.generate(), $.keypair.generate()]);
+      const [payer, recipient] = await $.airdrop($.keypair.several(2));
       // Associated token account already existing (to test if it breaks the transfer completion):
       const recipientTokenAccount = await spl.createAssociatedTokenAccount(
         $.connection,
@@ -609,7 +642,7 @@ describe('Token Bridge Relayer Program', () => {
         { chain: ETHEREUM, tokenBridge: ethereumTokenBridge, tbrPeer: ethereumTbrPeer1 },
         {
           recipient: new UniversalAddress(recipient.publicKey.toBuffer()),
-          gasDropoff: 0.1, // We want 0.1 SOL
+          gasDropoff: 0.1, // SOL
           unwrapIntent: false,
         },
       );
@@ -673,7 +706,7 @@ describe('Token Bridge Relayer Program', () => {
         userTokenAccount: recipientTokenAccountForeignToken,
         transferredAmount,
         gasDropoffAmount,
-        maxFeeLamports: 100_000_000n, // 0.1SOL max
+        maxFeeLamports: sol(0.1),
         unwrapIntent,
         mintAddress: (await tokenBridgeClient.client.getWrappedAsset({
           address: ethereumTokenAddressFoo,
@@ -705,6 +738,27 @@ describe('Token Bridge Relayer Program', () => {
       expect(vaa.payload.payload.recipient).deep.equal(foreignAddress);
     });
 
+    it('Fails to transfer a token due to dropoff exceeding maximum', async () => {
+      const gasDropoffAmount = 11;
+      const unwrapIntent = false;
+      const transferredAmount = 321654n;
+
+      const tokenAccount = await barMint.mint(1_000_000_000n, unauthorizedClient.signer);
+
+      const foreignAddress = $.universalAddress.generate();
+
+      const transferPromise = unauthorizedClient.transferTokens({
+        recipient: { address: foreignAddress, chain: ETHEREUM },
+        userTokenAccount: tokenAccount.publicKey,
+        transferredAmount,
+        gasDropoffAmount,
+        maxFeeLamports: sol(0.1),
+        unwrapIntent,
+        mintAddress: barMint.address,
+      });
+      await assert.promise(transferPromise).failsWith('DropoffExceedingMaximum');
+    });
+
     after(async () => {
       await clientForeignToken.close();
     });
diff --git a/solana/tests/utils/helpers.ts b/solana/tests/utils/helpers.ts
index 4d9564ac..356d7e3f 100644
--- a/solana/tests/utils/helpers.ts
+++ b/solana/tests/utils/helpers.ts
@@ -27,8 +27,6 @@ import { isTypedArray } from 'util/types';
 
 const execAsync = promisify(exec);
 
-const LOCALHOST = 'http://localhost:8899';
-
 export interface ErrorConstructor {
   new (...args: any[]): Error;
 }
@@ -105,6 +103,10 @@ function extractPubkey(from: HasPublicKey): PublicKey {
   }
 }
 
+type Tuple<T, N extends number, R extends T[] = []> = R['length'] extends N
+  ? R
+  : Tuple<T, N, [T, ...R]>;
+
 export class TestsHelper {
   static readonly LOCALHOST = 'http://localhost:8899';
   readonly connection: Connection;
@@ -115,7 +117,7 @@ export class TestsHelper {
 
   constructor(finality: Finality = 'confirmed') {
     if (TestsHelper.connections[finality] === undefined) {
-      TestsHelper.connections[finality] = new Connection(LOCALHOST, finality);
+      TestsHelper.connections[finality] = new Connection(TestsHelper.LOCALHOST, finality);
     }
     this.connection = TestsHelper.connections[finality];
     this.finality = finality;
@@ -126,7 +128,8 @@ export class TestsHelper {
     read: async (path: string): Promise<PublicKey> =>
       this.keypair.read(path).then((kp) => kp.publicKey),
     from: (hasPublicKey: HasPublicKey): PublicKey => extractPubkey(hasPublicKey),
-    several: (amount: number): PublicKey[] => Array.from({ length: amount }).map(PublicKey.unique),
+    several: <N extends number>(amount: number): Tuple<PublicKey, N> =>
+      Array.from({ length: amount }).map(PublicKey.unique) as Tuple<PublicKey, N>,
   };
 
   keypair = {
@@ -134,7 +137,8 @@ export class TestsHelper {
     read: async (path: string): Promise<Keypair> =>
       this.keypair.from(JSON.parse(await fs.readFile(path, { encoding: 'utf8' }))),
     from: (bytes: number[]): Keypair => Keypair.fromSecretKey(Uint8Array.from(bytes)),
-    several: (amount: number): Keypair[] => Array.from({ length: amount }).map(Keypair.generate),
+    several: <N extends number>(amount: N): Tuple<Keypair, N> =>
+      Array.from({ length: amount }).map(Keypair.generate) as Tuple<Keypair, N>,
   };
 
   universalAddress = {
@@ -144,8 +148,14 @@ export class TestsHelper {
             Buffer.concat([Buffer.alloc(12), PublicKey.unique().toBuffer().subarray(12)]),
           )
         : new UniversalAddress(PublicKey.unique().toBuffer()),
-    several: (amount: number, ethereum?: 'ethereum'): UniversalAddress[] =>
-      Array.from({ length: amount }).map(() => this.universalAddress.generate(ethereum)),
+    several: <N extends number>(
+      amount: number,
+      ethereum?: 'ethereum',
+    ): Tuple<UniversalAddress, N> =>
+      Array.from({ length: amount }).map(() => this.universalAddress.generate(ethereum)) as Tuple<
+        UniversalAddress,
+        N
+      >,
   };
 
   /** Waits that a transaction is confirmed. */
@@ -231,7 +241,7 @@ export class TestsHelper {
 
     // Deploy:
     await execAsync(
-      `solana --url ${LOCALHOST} -k ${authorityKeypair} program deploy ${binary} --program-id ${programKeypair}`,
+      `solana --url ${TestsHelper.LOCALHOST} -k ${authorityKeypair} program deploy ${binary} --program-id ${programKeypair}`,
     );
 
     // Wait for deploy to be finalized. Don't remove.
diff --git a/solana/tests/utils/tbr-wrapper.ts b/solana/tests/utils/tbr-wrapper.ts
index fa9f7b5c..2757d61d 100644
--- a/solana/tests/utils/tbr-wrapper.ts
+++ b/solana/tests/utils/tbr-wrapper.ts
@@ -92,9 +92,9 @@ export class TbrWrapper {
     );
   }
 
-  async confirmOwnerTransferRequest(owner: Signer): Promise<VersionedTransactionResponse | null> {
+  async confirmOwnerTransferRequest(): Promise<VersionedTransactionResponse | null> {
     return $.getTransaction(
-      $.sendAndConfirm(await this.client.confirmOwnerTransferRequest(), this.signer, owner),
+      $.sendAndConfirm(await this.client.confirmOwnerTransferRequest(), this.signer),
     );
   }
 
@@ -114,13 +114,30 @@ export class TbrWrapper {
     );
   }
 
-  async registerPeer(
+  async registerFirstPeer(
     chain: Chain,
     peerAddress: UniversalAddress,
+    config: {
+      maxGasDropoffMicroToken: number;
+      relayerFeeMicroUsd: number;
+      pausedOutboundTransfers: boolean;
+    },
   ): Promise<VersionedTransactionResponse | null> {
     return $.getTransaction(
       $.sendAndConfirm(
-        await this.client.registerPeer(this.publicKey, chain, peerAddress),
+        await this.client.registerFirstPeer(this.publicKey, chain, peerAddress, config),
+        this.signer,
+      ),
+    );
+  }
+
+  async registerAdditionalPeer(
+    chain: Chain,
+    peerAddress: UniversalAddress,
+  ): Promise<VersionedTransactionResponse | null> {
+    return $.getTransaction(
+      $.sendAndConfirm(
+        await this.client.registerAdditionalPeer(this.publicKey, chain, peerAddress),
         this.signer,
       ),
     );
@@ -165,7 +182,7 @@ export class TbrWrapper {
   ): Promise<VersionedTransactionResponse | null> {
     return $.getTransaction(
       $.sendAndConfirm(
-        await this.client.updateRelayerFee(this.publicKey, chain, relayerFee),
+        await this.client.updateBaseFee(this.publicKey, chain, relayerFee),
         this.signer,
       ),
     );
diff --git a/target/idl/token_bridge_relayer.json b/target/idl/token_bridge_relayer.json
index 353f806e..648ac6e3 100644
--- a/target/idl/token_bridge_relayer.json
+++ b/target/idl/token_bridge_relayer.json
@@ -1,5 +1,5 @@
 {
-  "address": "HrZSAEW9QVbC4kQu51C7oFMHaam18AvAhpbBYeY9mKht",
+  "address": "ttbrcA1ckR3D3Ff4VR1MJNCvA7t4d4XV9TcvrVp4AoM",
   "metadata": {
     "name": "token_bridge_relayer",
     "version": "3.0.0",
@@ -110,6 +110,116 @@
             "because we will update roles depending on the operation."
           ],
           "writable": true
+        },
+        {
+          "name": "upgrade_lock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "name": "program_data",
+          "writable": true,
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  13,
+                  74,
+                  247,
+                  118,
+                  36,
+                  164,
+                  201,
+                  97,
+                  25,
+                  221,
+                  241,
+                  144,
+                  142,
+                  148,
+                  63,
+                  218,
+                  160,
+                  137,
+                  78,
+                  28,
+                  18,
+                  140,
+                  195,
+                  112,
+                  127,
+                  26,
+                  150,
+                  227,
+                  211,
+                  125,
+                  216,
+                  108
+                ]
+              }
+            ],
+            "program": {
+              "kind": "const",
+              "value": [
+                2,
+                168,
+                246,
+                145,
+                78,
+                136,
+                161,
+                176,
+                226,
+                16,
+                21,
+                62,
+                247,
+                99,
+                174,
+                43,
+                0,
+                194,
+                185,
+                61,
+                22,
+                193,
+                36,
+                210,
+                192,
+                83,
+                122,
+                16,
+                4,
+                128,
+                0,
+                0
+              ]
+            }
+          }
+        },
+        {
+          "name": "bpf_loader_upgradeable",
+          "address": "BPFLoaderUpgradeab1e11111111111111111111111"
         }
       ],
       "args": []
@@ -281,7 +391,10 @@
           "writable": true
         },
         {
-          "name": "peer"
+          "name": "peer",
+          "docs": [
+            "The TBR peer (_i.e._ `data().from_address()`). We do not care about the Token Bridge peer `vaa.meta.emitter_address`."
+          ]
         },
         {
           "name": "token_bridge_config"
@@ -431,10 +544,6 @@
             ]
           }
         },
-        {
-          "name": "previous_owner",
-          "signer": true
-        },
         {
           "name": "auth_badge_previous_owner",
           "writable": true,
@@ -471,6 +580,30 @@
           ],
           "writable": true
         },
+        {
+          "name": "upgrade_lock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
         {
           "name": "program_data",
           "writable": true,
@@ -587,10 +720,7 @@
           "signer": true
         },
         {
-          "name": "owner",
-          "docs": [
-            "The designated owner of the program."
-          ]
+          "name": "owner"
         },
         {
           "name": "auth_badge",
@@ -622,7 +752,7 @@
           "name": "tbr_config",
           "docs": [
             "Owner Config account. This program requires that the `owner` specified",
-            "in the context equals the pubkey specified in this account. Mutable."
+            "in the context equals the pubkey specified in this account."
           ],
           "writable": true,
           "pda": {
@@ -818,13 +948,6 @@
             "Proof that the signer is authorized."
           ]
         },
-        {
-          "name": "tbr_config",
-          "docs": [
-            "Owner Config account. This program requires that the `signer` specified",
-            "in the context equals an authorized pubkey specified in this account."
-          ]
-        },
         {
           "name": "peer",
           "writable": true,
@@ -1047,14 +1170,6 @@
         {
           "name": "chain_config",
           "writable": true
-        },
-        {
-          "name": "tbr_config",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1067,7 +1182,12 @@
     {
       "name": "submit_owner_transfer_request",
       "docs": [
-        "Updates the owner account. This needs to be either cancelled or approved."
+        "Updates the owner account. This needs to be either cancelled or approved.",
+        "",
+        "For safety reasons, transferring ownership is a 2-step process. This first step is to set the",
+        "new owner, and the second step is for the new owner to claim the ownership.",
+        "This is to prevent a situation where the ownership is transferred to an",
+        "address that is not able to claim the ownership (by mistake)."
       ],
       "discriminator": [
         99,
@@ -1110,6 +1230,116 @@
               }
             ]
           }
+        },
+        {
+          "name": "upgrade_lock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "name": "program_data",
+          "writable": true,
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  13,
+                  74,
+                  247,
+                  118,
+                  36,
+                  164,
+                  201,
+                  97,
+                  25,
+                  221,
+                  241,
+                  144,
+                  142,
+                  148,
+                  63,
+                  218,
+                  160,
+                  137,
+                  78,
+                  28,
+                  18,
+                  140,
+                  195,
+                  112,
+                  127,
+                  26,
+                  150,
+                  227,
+                  211,
+                  125,
+                  216,
+                  108
+                ]
+              }
+            ],
+            "program": {
+              "kind": "const",
+              "value": [
+                2,
+                168,
+                246,
+                145,
+                78,
+                136,
+                161,
+                176,
+                226,
+                16,
+                21,
+                62,
+                247,
+                99,
+                174,
+                43,
+                0,
+                194,
+                185,
+                61,
+                22,
+                193,
+                36,
+                210,
+                192,
+                83,
+                122,
+                16,
+                4,
+                128,
+                0,
+                0
+              ]
+            }
+          }
+        },
+        {
+          "name": "bpf_loader_upgradeable",
+          "address": "BPFLoaderUpgradeab1e11111111111111111111111"
         }
       ],
       "args": [
@@ -1193,9 +1423,6 @@
         },
         {
           "name": "fee_recipient",
-          "docs": [
-            "Fee recipient's account. The fee will be transferred to this account."
-          ],
           "writable": true,
           "relations": [
             "tbr_config"
@@ -1381,18 +1608,7 @@
           "docs": [
             "Owner of the program as set in the [`TbrConfig`] account."
           ],
-          "writable": true,
-          "signer": true,
-          "relations": [
-            "tbr_config"
-          ]
-        },
-        {
-          "name": "tbr_config",
-          "docs": [
-            "Owner Config account. This program requires that the `owner` specified",
-            "in the context equals the `owner` pubkey specified in this account."
-          ]
+          "signer": true
         },
         {
           "name": "peer"
@@ -1549,14 +1765,6 @@
         {
           "name": "chain_config",
           "writable": true
-        },
-        {
-          "name": "tbr_config",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1604,14 +1812,6 @@
         {
           "name": "chain_config",
           "writable": true
-        },
-        {
-          "name": "tbr_config",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1753,63 +1953,73 @@
     },
     {
       "code": 6007,
+      "name": "DropoffExceedingMaximum",
+      "msg": "DropoffExceedingMaximum"
+    },
+    {
+      "code": 6008,
       "name": "FeeExceedingMaximum",
       "msg": "FeeExceedingMaximum"
     },
     {
-      "code": 6008,
+      "code": 6009,
       "name": "WrongFeeRecipient",
       "msg": "WrongFeeRecipient"
     },
     {
-      "code": 6009,
+      "code": 6010,
       "name": "WronglySetOptionalAccounts",
       "msg": "WronglySetOptionalAccounts"
     },
     {
-      "code": 6010,
+      "code": 6011,
       "name": "WrongMintAuthority",
       "msg": "WrongMintAuthority"
     },
     {
-      "code": 6011,
+      "code": 6012,
       "name": "InvalidRecipient",
       "msg": "InvalidRecipient"
     },
     {
-      "code": 6012,
+      "code": 6013,
       "name": "EvmChainPriceNotSet",
       "msg": "EvmChainPriceNotSet"
     },
     {
-      "code": 6013,
+      "code": 6014,
       "name": "ChainPriceMismatch",
       "msg": "ChainPriceMismatch"
     },
     {
-      "code": 6014,
+      "code": 6015,
       "name": "PausedTransfers",
       "msg": "PausedTransfers"
     },
     {
-      "code": 6015,
+      "code": 6016,
       "name": "InvalidSendingPeer",
       "msg": "InvalidSendingPeer"
     },
     {
-      "code": 6016,
+      "code": 6017,
       "name": "CannotRegisterSolana",
       "msg": "CannotRegisterSolana"
     },
     {
-      "code": 6017,
+      "code": 6018,
       "name": "InvalidPeerAddress",
       "msg": "InvalidPeerAddress"
     },
     {
-      "code": 6018,
+      "code": 6019,
       "name": "MissingAssociatedTokenAccount",
       "msg": "MissingAssociatedTokenAccount"
+    },
+    {
+      "code": 6020,
+      "name": "Overflow",
+      "msg": "Overflow"
     }
   ],
   "types": [
@@ -2053,6 +2263,11 @@
       "name": "SEED_PREFIX_TEMPORARY",
       "type": "bytes",
       "value": "[116, 109, 112]"
+    },
+    {
+      "name": "SEED_PREFIX_UPGRADE_LOCK",
+      "type": "bytes",
+      "value": "[117, 112, 103, 114, 97, 100, 101, 32, 108, 111, 99, 107]"
     }
   ]
 }
\ No newline at end of file
diff --git a/target/types/token_bridge_relayer.ts b/target/types/token_bridge_relayer.ts
index 360f6270..bad574fe 100644
--- a/target/types/token_bridge_relayer.ts
+++ b/target/types/token_bridge_relayer.ts
@@ -116,6 +116,116 @@ export type TokenBridgeRelayer = {
             "because we will update roles depending on the operation."
           ],
           "writable": true
+        },
+        {
+          "name": "upgradeLock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "name": "programData",
+          "writable": true,
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  13,
+                  74,
+                  247,
+                  118,
+                  36,
+                  164,
+                  201,
+                  97,
+                  25,
+                  221,
+                  241,
+                  144,
+                  142,
+                  148,
+                  63,
+                  218,
+                  160,
+                  137,
+                  78,
+                  28,
+                  18,
+                  140,
+                  195,
+                  112,
+                  127,
+                  26,
+                  150,
+                  227,
+                  211,
+                  125,
+                  216,
+                  108
+                ]
+              }
+            ],
+            "program": {
+              "kind": "const",
+              "value": [
+                2,
+                168,
+                246,
+                145,
+                78,
+                136,
+                161,
+                176,
+                226,
+                16,
+                21,
+                62,
+                247,
+                99,
+                174,
+                43,
+                0,
+                194,
+                185,
+                61,
+                22,
+                193,
+                36,
+                210,
+                192,
+                83,
+                122,
+                16,
+                4,
+                128,
+                0,
+                0
+              ]
+            }
+          }
+        },
+        {
+          "name": "bpfLoaderUpgradeable",
+          "address": "BPFLoaderUpgradeab1e11111111111111111111111"
         }
       ],
       "args": []
@@ -287,7 +397,10 @@ export type TokenBridgeRelayer = {
           "writable": true
         },
         {
-          "name": "peer"
+          "name": "peer",
+          "docs": [
+            "The TBR peer (_i.e._ `data().from_address()`). We do not care about the Token Bridge peer `vaa.meta.emitter_address`."
+          ]
         },
         {
           "name": "tokenBridgeConfig"
@@ -437,10 +550,6 @@ export type TokenBridgeRelayer = {
             ]
           }
         },
-        {
-          "name": "previousOwner",
-          "signer": true
-        },
         {
           "name": "authBadgePreviousOwner",
           "writable": true,
@@ -477,6 +586,30 @@ export type TokenBridgeRelayer = {
           ],
           "writable": true
         },
+        {
+          "name": "upgradeLock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
         {
           "name": "programData",
           "writable": true,
@@ -593,10 +726,7 @@ export type TokenBridgeRelayer = {
           "signer": true
         },
         {
-          "name": "owner",
-          "docs": [
-            "The designated owner of the program."
-          ]
+          "name": "owner"
         },
         {
           "name": "authBadge",
@@ -628,7 +758,7 @@ export type TokenBridgeRelayer = {
           "name": "tbrConfig",
           "docs": [
             "Owner Config account. This program requires that the `owner` specified",
-            "in the context equals the pubkey specified in this account. Mutable."
+            "in the context equals the pubkey specified in this account."
           ],
           "writable": true,
           "pda": {
@@ -824,13 +954,6 @@ export type TokenBridgeRelayer = {
             "Proof that the signer is authorized."
           ]
         },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Owner Config account. This program requires that the `signer` specified",
-            "in the context equals an authorized pubkey specified in this account."
-          ]
-        },
         {
           "name": "peer",
           "writable": true,
@@ -1053,14 +1176,6 @@ export type TokenBridgeRelayer = {
         {
           "name": "chainConfig",
           "writable": true
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1073,7 +1188,12 @@ export type TokenBridgeRelayer = {
     {
       "name": "submitOwnerTransferRequest",
       "docs": [
-        "Updates the owner account. This needs to be either cancelled or approved."
+        "Updates the owner account. This needs to be either cancelled or approved.",
+        "",
+        "For safety reasons, transferring ownership is a 2-step process. This first step is to set the",
+        "new owner, and the second step is for the new owner to claim the ownership.",
+        "This is to prevent a situation where the ownership is transferred to an",
+        "address that is not able to claim the ownership (by mistake)."
       ],
       "discriminator": [
         99,
@@ -1116,6 +1236,116 @@ export type TokenBridgeRelayer = {
               }
             ]
           }
+        },
+        {
+          "name": "upgradeLock",
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  117,
+                  112,
+                  103,
+                  114,
+                  97,
+                  100,
+                  101,
+                  32,
+                  108,
+                  111,
+                  99,
+                  107
+                ]
+              }
+            ]
+          }
+        },
+        {
+          "name": "programData",
+          "writable": true,
+          "pda": {
+            "seeds": [
+              {
+                "kind": "const",
+                "value": [
+                  13,
+                  74,
+                  247,
+                  118,
+                  36,
+                  164,
+                  201,
+                  97,
+                  25,
+                  221,
+                  241,
+                  144,
+                  142,
+                  148,
+                  63,
+                  218,
+                  160,
+                  137,
+                  78,
+                  28,
+                  18,
+                  140,
+                  195,
+                  112,
+                  127,
+                  26,
+                  150,
+                  227,
+                  211,
+                  125,
+                  216,
+                  108
+                ]
+              }
+            ],
+            "program": {
+              "kind": "const",
+              "value": [
+                2,
+                168,
+                246,
+                145,
+                78,
+                136,
+                161,
+                176,
+                226,
+                16,
+                21,
+                62,
+                247,
+                99,
+                174,
+                43,
+                0,
+                194,
+                185,
+                61,
+                22,
+                193,
+                36,
+                210,
+                192,
+                83,
+                122,
+                16,
+                4,
+                128,
+                0,
+                0
+              ]
+            }
+          }
+        },
+        {
+          "name": "bpfLoaderUpgradeable",
+          "address": "BPFLoaderUpgradeab1e11111111111111111111111"
         }
       ],
       "args": [
@@ -1199,9 +1429,6 @@ export type TokenBridgeRelayer = {
         },
         {
           "name": "feeRecipient",
-          "docs": [
-            "Fee recipient's account. The fee will be transferred to this account."
-          ],
           "writable": true,
           "relations": [
             "tbrConfig"
@@ -1387,18 +1614,7 @@ export type TokenBridgeRelayer = {
           "docs": [
             "Owner of the program as set in the [`TbrConfig`] account."
           ],
-          "writable": true,
-          "signer": true,
-          "relations": [
-            "tbrConfig"
-          ]
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Owner Config account. This program requires that the `owner` specified",
-            "in the context equals the `owner` pubkey specified in this account."
-          ]
+          "signer": true
         },
         {
           "name": "peer"
@@ -1555,14 +1771,6 @@ export type TokenBridgeRelayer = {
         {
           "name": "chainConfig",
           "writable": true
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1610,14 +1818,6 @@ export type TokenBridgeRelayer = {
         {
           "name": "chainConfig",
           "writable": true
-        },
-        {
-          "name": "tbrConfig",
-          "docs": [
-            "Program Config account. This program requires that the [`signer`] specified",
-            "in the context equals a pubkey specified in this account. Mutable,",
-            "because we will update roles depending on the operation."
-          ]
         }
       ],
       "args": [
@@ -1759,63 +1959,73 @@ export type TokenBridgeRelayer = {
     },
     {
       "code": 6007,
+      "name": "dropoffExceedingMaximum",
+      "msg": "dropoffExceedingMaximum"
+    },
+    {
+      "code": 6008,
       "name": "feeExceedingMaximum",
       "msg": "feeExceedingMaximum"
     },
     {
-      "code": 6008,
+      "code": 6009,
       "name": "wrongFeeRecipient",
       "msg": "wrongFeeRecipient"
     },
     {
-      "code": 6009,
+      "code": 6010,
       "name": "wronglySetOptionalAccounts",
       "msg": "wronglySetOptionalAccounts"
     },
     {
-      "code": 6010,
+      "code": 6011,
       "name": "wrongMintAuthority",
       "msg": "wrongMintAuthority"
     },
     {
-      "code": 6011,
+      "code": 6012,
       "name": "invalidRecipient",
       "msg": "invalidRecipient"
     },
     {
-      "code": 6012,
+      "code": 6013,
       "name": "evmChainPriceNotSet",
       "msg": "evmChainPriceNotSet"
     },
     {
-      "code": 6013,
+      "code": 6014,
       "name": "chainPriceMismatch",
       "msg": "chainPriceMismatch"
     },
     {
-      "code": 6014,
+      "code": 6015,
       "name": "pausedTransfers",
       "msg": "pausedTransfers"
     },
     {
-      "code": 6015,
+      "code": 6016,
       "name": "invalidSendingPeer",
       "msg": "invalidSendingPeer"
     },
     {
-      "code": 6016,
+      "code": 6017,
       "name": "cannotRegisterSolana",
       "msg": "cannotRegisterSolana"
     },
     {
-      "code": 6017,
+      "code": 6018,
       "name": "invalidPeerAddress",
       "msg": "invalidPeerAddress"
     },
     {
-      "code": 6018,
+      "code": 6019,
       "name": "missingAssociatedTokenAccount",
       "msg": "missingAssociatedTokenAccount"
+    },
+    {
+      "code": 6020,
+      "name": "overflow",
+      "msg": "overflow"
     }
   ],
   "types": [
@@ -2059,6 +2269,11 @@ export type TokenBridgeRelayer = {
       "name": "seedPrefixTemporary",
       "type": "bytes",
       "value": "[116, 109, 112]"
+    },
+    {
+      "name": "seedPrefixUpgradeLock",
+      "type": "bytes",
+      "value": "[117, 112, 103, 114, 97, 100, 101, 32, 108, 111, 99, 107]"
     }
   ]
 };