diff --git a/.github/workflows/node-ci.yml b/.github/workflows/node-ci.yml
index 9ed07ff47..f2579e2c2 100644
--- a/.github/workflows/node-ci.yml
+++ b/.github/workflows/node-ci.yml
@@ -163,7 +163,7 @@ jobs:
         #Requires permissions.checks: write
       - name: Publish test results
         if: ${{ inputs.output-test-results && always() }}
-        uses: phoenix-actions/test-reporting@v10
+        uses: phoenix-actions/test-reporting@v15
         with:
           name: Test results
           path: ${{ inputs.test-results-file-pattern }}
diff --git a/package-lock.json b/package-lock.json
index b25292c3b..2b10da0b3 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -13544,7 +13544,7 @@
     },
     "packages/algo-ts/dist": {
       "name": "@algorandfoundation/algorand-typescript",
-      "version": "1.0.0-beta.8",
+      "version": "1.0.0-beta.9",
       "dev": true,
       "peerDependencies": {
         "tslib": "^2.6.2"
diff --git a/packages/algo-ts/package.json b/packages/algo-ts/package.json
index 22e8e6dfb..fc178117c 100644
--- a/packages/algo-ts/package.json
+++ b/packages/algo-ts/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@algorandfoundation/algorand-typescript",
-  "version": "1.0.0-beta.8",
+  "version": "1.0.0-beta.9",
   "description": "This package contains definitions for the types which comprise Algorand TypeScript which can be compiled to run on the Algorand Virtual Machine using the Puya compiler.",
   "private": false,
   "main": "index.js",
diff --git a/packages/algo-ts/src/arc4/encoded-types.ts b/packages/algo-ts/src/arc4/encoded-types.ts
index 2701fe561..4f1a03a28 100644
--- a/packages/algo-ts/src/arc4/encoded-types.ts
+++ b/packages/algo-ts/src/arc4/encoded-types.ts
@@ -285,7 +285,7 @@ class StructImpl<T extends StructConstraint> extends StructBase {
   }
 }
 
-type StructConstructor = new <T extends StructConstraint>(initial: T) => StructBase & T
+type StructConstructor = new <T extends StructConstraint>(initial: T) => StructBase & Readonly<T>
 
 export const Struct = StructImpl as StructConstructor
 
diff --git a/src/awst_build/arc4-util.ts b/src/awst_build/arc4-util.ts
index 622bc59ff..c0267deda 100644
--- a/src/awst_build/arc4-util.ts
+++ b/src/awst_build/arc4-util.ts
@@ -74,6 +74,7 @@ export function ptypeToArc4EncodedType(ptype: PType, sourceLocation: SourceLocat
       module: ptype.module,
       description: ptype.description,
       fields: Object.fromEntries(ptype.orderedProperties().map(([p, pt]) => [p, ptypeToArc4EncodedType(pt, sourceLocation)])),
+      frozen: true,
     })
 
   throw new CodeError(`${ptype} cannot be encoded to an ARC4 type`, { sourceLocation })
diff --git a/src/awst_build/eb/arc28/arc-28-emit-function-builder.ts b/src/awst_build/eb/arc28/arc-28-emit-function-builder.ts
index f9b13d2ee..318ed91e1 100644
--- a/src/awst_build/eb/arc28/arc-28-emit-function-builder.ts
+++ b/src/awst_build/eb/arc28/arc-28-emit-function-builder.ts
@@ -75,6 +75,7 @@ export class Arc28EmitFunctionBuilder extends FunctionBuilder {
         fields,
         description: undefined,
         sourceLocation,
+        frozen: true,
       })
       const structExpression = nodeFactory.newStruct({
         wtype: structType.wtype,
diff --git a/src/awst_build/ptypes/arc4-types.ts b/src/awst_build/ptypes/arc4-types.ts
index e56a97f87..45bde8914 100644
--- a/src/awst_build/ptypes/arc4-types.ts
+++ b/src/awst_build/ptypes/arc4-types.ts
@@ -131,8 +131,10 @@ export class ARC4StructType extends ARC4EncodedType {
   readonly singleton = false
   readonly fields: Record<string, ARC4EncodedType>
   readonly sourceLocation: SourceLocation | undefined
+  readonly frozen: boolean
   constructor({
     name,
+    frozen,
     module,
     fields,
     description,
@@ -140,6 +142,7 @@ export class ARC4StructType extends ARC4EncodedType {
   }: {
     name: string
     module: string
+    frozen: boolean
     description: string | undefined
     fields: Record<string, ARC4EncodedType>
     sourceLocation?: SourceLocation
@@ -147,6 +150,7 @@ export class ARC4StructType extends ARC4EncodedType {
     super()
     this.name = name
     this.module = module
+    this.frozen = frozen
     this.fields = fields
     this.description = description
     this.sourceLocation = sourceLocation
@@ -162,7 +166,7 @@ export class ARC4StructType extends ARC4EncodedType {
       fields: Object.fromEntries(Object.entries(this.fields).map(([f, t]) => [f, t.wtype])),
       sourceLocation: this.sourceLocation,
       desc: this.description ?? null,
-      frozen: false,
+      frozen: this.frozen,
     })
   }
 
@@ -189,6 +193,7 @@ export const arc4StructBaseType = new ARC4StructType({
   module: Constants.arc4EncodedTypesModuleName,
   fields: {},
   description: undefined,
+  frozen: true,
 })
 
 export const Arc4TupleClass = new LibClassType({
diff --git a/src/awst_build/type-resolver.ts b/src/awst_build/type-resolver.ts
index ad7b0008b..30dff967c 100644
--- a/src/awst_build/type-resolver.ts
+++ b/src/awst_build/type-resolver.ts
@@ -362,6 +362,7 @@ export class TypeResolver {
       fields: fields,
       sourceLocation: sourceLocation,
       description: tryGetTypeDescription(tsType),
+      frozen: baseType.frozen,
     })
   }
 
diff --git a/src/constants.ts b/src/constants.ts
index abfc26de0..7fb4f94d1 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -34,8 +34,7 @@ export const Constants = {
   zeroAddressEncoded: 'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAY5HFKQ',
 
   supportedAvmVersions: [10n, 11n],
-  mainNetAvmVersion: [10n],
-  targetedPuyaVersion: '4.1.1',
+  targetedPuyaVersion: '4.2.0',
 } as const
 
 export type SupportedAvmVersion = (typeof Constants.supportedAvmVersions)[number]
diff --git a/src/puya/check-puya-version.ts b/src/puya/check-puya-version.ts
index 142e7eac5..c8fbceb1d 100644
--- a/src/puya/check-puya-version.ts
+++ b/src/puya/check-puya-version.ts
@@ -2,7 +2,21 @@ import { Constants } from '../constants'
 import { logger } from '../logger'
 import { runPuya } from './run-puya'
 
-export function checkPuyaVersion() {
+export enum VersionCompareVerdict {
+  ExactMatch = 'ExactMatch',
+  Inconclusive = 'Inconclusive',
+  MajorMismatch = 'MajorMismatch',
+  MinorMismatch = 'MinorMismatch',
+  RevisionMismatch = 'RevisionMismatch',
+}
+
+export function comparePuyaVersion(): {
+  target: string
+  found?: string
+  verdict: VersionCompareVerdict
+} {
+  const target = Constants.targetedPuyaVersion
+
   const versionParser = new VersionParser()
   runPuya({
     command: 'puya',
@@ -10,23 +24,36 @@ export function checkPuyaVersion() {
     onOutput: (line) => versionParser.receiveLine(line),
   })
 
-  if (versionParser.version) {
-    const ver = versionParser.version
-    // Compare
-    const [major, minor, rev] = Constants.targetedPuyaVersion.split('.').map((x) => Number(x))
-    if (major !== ver.major || minor !== ver.minor) {
+  if (!versionParser.version) return { target, verdict: VersionCompareVerdict.Inconclusive }
+  const ver = versionParser.version
+
+  // Compare
+  const [major, minor, rev] = target.split('.').map((x) => Number(x))
+  if (ver.major !== major) return { verdict: VersionCompareVerdict.MajorMismatch, target, found: ver.formatted }
+  if (ver.minor !== minor) return { verdict: VersionCompareVerdict.MinorMismatch, target, found: ver.formatted }
+  if (ver.rev !== rev) return { verdict: VersionCompareVerdict.RevisionMismatch, target, found: ver.formatted }
+  return { verdict: VersionCompareVerdict.ExactMatch, target, found: ver.formatted }
+}
+
+export function checkPuyaVersion() {
+  const result = comparePuyaVersion()
+  switch (result.verdict) {
+    case VersionCompareVerdict.Inconclusive:
+      logger.warn(undefined, `Unable to verify installed puya version. Please ensure version ${result.target} is available`)
+      break
+    case VersionCompareVerdict.MajorMismatch:
+    case VersionCompareVerdict.MinorMismatch:
       logger.warn(
         undefined,
-        `Installed version of puya (${ver.major}.${ver.minor}.${ver.rev}) does not match targeted version for puya-ts (${Constants.targetedPuyaVersion}). There may be compatability issues.`,
+        `Installed version of puya (${result.found}) does not match targeted version for puya-ts (${result.target}). There may be compatability issues.`,
       )
-    } else if (rev !== ver.rev) {
+      break
+    case VersionCompareVerdict.RevisionMismatch:
       logger.debug(
         undefined,
-        `Installed revision of puya (${ver.major}.${ver.minor}.${ver.rev}) does not match targeted revision for puya-ts (${Constants.targetedPuyaVersion})`,
+        `Installed revision of puya (${result.found}) does not match targeted revision for puya-ts (${Constants.targetedPuyaVersion})`,
       )
-    }
-  } else {
-    logger.warn(undefined, `Unable to verify installed puya version. Please ensure version ${Constants.targetedPuyaVersion} is available`)
+      break
   }
 }
 
@@ -34,20 +61,22 @@ type SemVer = {
   major: number
   minor: number
   rev: number
+  formatted: string
 }
 
 class VersionParser {
   #ver: SemVer | undefined
 
   receiveLine(line: string): void {
-    const matched = /^puya (\d+)\.(\d+)\.(\d+)$/.exec(line)
+    const matched = /^puya ((\d+)\.(\d+)\.(\d+))$/.exec(line)
     if (!matched) {
       logger.debug(undefined, `'puya --version' command returned unexpected output: "${line}"`)
     } else {
       this.#ver = {
-        major: Number(matched[1]),
-        minor: Number(matched[2]),
-        rev: Number(matched[3]),
+        formatted: matched[1],
+        major: Number(matched[2]),
+        minor: Number(matched[3]),
+        rev: Number(matched[4]),
       }
     }
   }
diff --git a/tests/approvals/out/arc-28-events/arc-28-events.awst.json b/tests/approvals/out/arc-28-events/arc-28-events.awst.json
index 55096f772..b975591af 100644
--- a/tests/approvals/out/arc-28-events/arc-28-events.awst.json
+++ b/tests/approvals/out/arc-28-events/arc-28-events.awst.json
@@ -321,7 +321,7 @@
                       }
                     },
                     "source_location": null,
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "value": {
@@ -1027,7 +1027,7 @@
                       }
                     },
                     "source_location": null,
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "value": {
@@ -1156,7 +1156,7 @@
                     "column": 10,
                     "end_column": 11
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "name": "y"
@@ -1219,7 +1219,7 @@
                     "column": 18,
                     "end_column": 29
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "values": {
@@ -1698,7 +1698,7 @@
                       "column": 9,
                       "end_column": 10
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "name": "y"
@@ -1789,7 +1789,7 @@
                       "column": 4,
                       "end_column": 25
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "values": {
@@ -1935,7 +1935,7 @@
                       "column": 4,
                       "end_column": 38
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "values": {
@@ -2109,7 +2109,7 @@
                       "column": 4,
                       "end_column": 60
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "values": {
@@ -2500,7 +2500,7 @@
                       "column": 4,
                       "end_column": 30
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "values": {
@@ -2710,7 +2710,7 @@
                       "column": 4,
                       "end_column": 43
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "values": {
@@ -3058,7 +3058,7 @@
                       "column": 4,
                       "end_column": 35
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "values": {
diff --git a/tests/approvals/out/arc4-encode-decode/arc4-encode-decode.awst.json b/tests/approvals/out/arc4-encode-decode/arc4-encode-decode.awst.json
index 6253c1887..79a736f9d 100644
--- a/tests/approvals/out/arc4-encode-decode/arc4-encode-decode.awst.json
+++ b/tests/approvals/out/arc4-encode-decode/arc4-encode-decode.awst.json
@@ -1306,7 +1306,7 @@
                           }
                         },
                         "source_location": null,
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "value": {
@@ -1477,7 +1477,7 @@
                           "column": 43,
                           "end_column": 53
                         },
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "values": {
@@ -3101,7 +3101,7 @@
                                 }
                               },
                               "source_location": null,
-                              "frozen": false,
+                              "frozen": true,
                               "desc": null
                             },
                             "expr": {
@@ -3457,7 +3457,7 @@
                                 }
                               },
                               "source_location": null,
-                              "frozen": false,
+                              "frozen": true,
                               "desc": null
                             },
                             "expr": {
diff --git a/tests/approvals/out/arc4-struct/arc4-struct.awst.json b/tests/approvals/out/arc4-struct/arc4-struct.awst.json
index 7745d3068..563564cd0 100644
--- a/tests/approvals/out/arc4-struct/arc4-struct.awst.json
+++ b/tests/approvals/out/arc4-struct/arc4-struct.awst.json
@@ -255,7 +255,7 @@
                     "column": 10,
                     "end_column": 12
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "name": "v1"
@@ -318,7 +318,7 @@
                     "column": 19,
                     "end_column": 25
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "values": {
@@ -844,7 +844,7 @@
                             "column": 8,
                             "end_column": 10
                           },
-                          "frozen": false,
+                          "frozen": true,
                           "desc": null
                         },
                         "name": "v1"
@@ -982,7 +982,7 @@
                             "column": 8,
                             "end_column": 10
                           },
-                          "frozen": false,
+                          "frozen": true,
                           "desc": null
                         },
                         "name": "v1"
@@ -1060,7 +1060,7 @@
                     "column": 10,
                     "end_column": 12
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "name": "v2"
@@ -1123,7 +1123,7 @@
                     "column": 19,
                     "end_column": 25
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "values": {
@@ -2309,7 +2309,7 @@
                           "column": 11,
                           "end_column": 13
                         },
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "name": "v1"
@@ -2390,7 +2390,7 @@
                           "column": 18,
                           "end_column": 20
                         },
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "name": "v2"
@@ -2494,7 +2494,7 @@
                 "column": 24,
                 "end_column": 30
               },
-              "frozen": false,
+              "frozen": true,
               "desc": null
             },
             "source_location": {
@@ -2557,7 +2557,7 @@
                 "column": 36,
                 "end_column": 42
               },
-              "frozen": false,
+              "frozen": true,
               "desc": null
             },
             "source_location": {
@@ -2618,7 +2618,7 @@
             "column": 2,
             "end_column": 43
           },
-          "frozen": false,
+          "frozen": true,
           "desc": null
         },
         "body": {
@@ -2698,7 +2698,7 @@
                     "column": 15,
                     "end_column": 21
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "values": {
@@ -2976,7 +2976,7 @@
                                         "column": 24,
                                         "end_column": 26
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v1"
@@ -3084,7 +3084,7 @@
                                         "column": 38,
                                         "end_column": 40
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v2"
@@ -3234,7 +3234,7 @@
                                         "column": 24,
                                         "end_column": 26
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v1"
@@ -3342,7 +3342,7 @@
                                         "column": 38,
                                         "end_column": 40
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v2"
@@ -3632,7 +3632,7 @@
                                         "column": 24,
                                         "end_column": 26
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v1"
@@ -3740,7 +3740,7 @@
                                         "column": 38,
                                         "end_column": 40
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v2"
@@ -3890,7 +3890,7 @@
                                         "column": 24,
                                         "end_column": 26
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v1"
@@ -3998,7 +3998,7 @@
                                         "column": 38,
                                         "end_column": 40
                                       },
-                                      "frozen": false,
+                                      "frozen": true,
                                       "desc": null
                                     },
                                     "name": "v2"
@@ -4151,7 +4151,7 @@
                 "column": 41,
                 "end_column": 47
               },
-              "frozen": false,
+              "frozen": true,
               "desc": null
             },
             "source_location": {
@@ -4247,7 +4247,7 @@
                     "column": 10,
                     "end_column": 12
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "name": "v2"
@@ -4310,7 +4310,7 @@
                     "column": 19,
                     "end_column": 25
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "values": {
@@ -4505,7 +4505,7 @@
                               "column": 26,
                               "end_column": 28
                             },
-                            "frozen": false,
+                            "frozen": true,
                             "desc": null
                           },
                           "name": "v1"
@@ -4706,7 +4706,7 @@
                               "column": 26,
                               "end_column": 28
                             },
-                            "frozen": false,
+                            "frozen": true,
                             "desc": null
                           },
                           "name": "v1"
@@ -4786,7 +4786,7 @@
                     "column": 10,
                     "end_column": 12
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "name": "v3"
@@ -4849,7 +4849,7 @@
                     "column": 19,
                     "end_column": 25
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "values": {
@@ -5070,7 +5070,7 @@
                                   "column": 31,
                                   "end_column": 33
                                 },
-                                "frozen": false,
+                                "frozen": true,
                                 "desc": null
                               },
                               "name": "v2"
@@ -5160,7 +5160,7 @@
                                   "column": 31,
                                   "end_column": 33
                                 },
-                                "frozen": false,
+                                "frozen": true,
                                 "desc": null
                               },
                               "name": "v2"
@@ -5390,7 +5390,7 @@
                                   "column": 31,
                                   "end_column": 33
                                 },
-                                "frozen": false,
+                                "frozen": true,
                                 "desc": null
                               },
                               "name": "v2"
@@ -5480,7 +5480,7 @@
                                   "column": 31,
                                   "end_column": 33
                                 },
-                                "frozen": false,
+                                "frozen": true,
                                 "desc": null
                               },
                               "name": "v2"
@@ -5611,7 +5611,7 @@
                           "column": 11,
                           "end_column": 13
                         },
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "name": "v1"
@@ -5692,7 +5692,7 @@
                           "column": 24,
                           "end_column": 26
                         },
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "name": "v2"
@@ -5817,7 +5817,7 @@
                           "column": 11,
                           "end_column": 13
                         },
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "name": "v3"
@@ -5898,7 +5898,7 @@
                           "column": 24,
                           "end_column": 26
                         },
-                        "frozen": false,
+                        "frozen": true,
                         "desc": null
                       },
                       "name": "v1"
@@ -6016,7 +6016,7 @@
                 "column": 28,
                 "end_column": 34
               },
-              "frozen": false,
+              "frozen": true,
               "desc": null
             },
             "source_location": {
@@ -6077,7 +6077,7 @@
             "column": 2,
             "end_column": 43
           },
-          "frozen": false,
+          "frozen": true,
           "desc": null
         },
         "body": {
@@ -6191,7 +6191,7 @@
                       "column": 21,
                       "end_column": 23
                     },
-                    "frozen": false,
+                    "frozen": true,
                     "desc": null
                   },
                   "name": "v1"
@@ -6265,7 +6265,7 @@
                     "column": 11,
                     "end_column": 44
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": null
                 },
                 "expr": {
diff --git a/tests/approvals/out/jsdoc/jsdoc.awst.json b/tests/approvals/out/jsdoc/jsdoc.awst.json
index fed7ed0f7..9af9da5f7 100644
--- a/tests/approvals/out/jsdoc/jsdoc.awst.json
+++ b/tests/approvals/out/jsdoc/jsdoc.awst.json
@@ -241,7 +241,7 @@
             "column": 2,
             "end_column": 39
           },
-          "frozen": false,
+          "frozen": true,
           "desc": "This is the description for demo struct"
         },
         "body": {
@@ -305,7 +305,7 @@
                     "column": 15,
                     "end_column": 25
                   },
-                  "frozen": false,
+                  "frozen": true,
                   "desc": "This is the description for demo struct"
                 },
                 "values": {
diff --git a/tests/check-version.spec.ts b/tests/check-version.spec.ts
new file mode 100644
index 000000000..4aa0697f9
--- /dev/null
+++ b/tests/check-version.spec.ts
@@ -0,0 +1,11 @@
+import { describe, expect, test } from 'vitest'
+import { comparePuyaVersion, VersionCompareVerdict } from '../src/puya/check-puya-version'
+
+describe('The puya version available for testing', () => {
+  test('must match the target version', () => {
+    const result = comparePuyaVersion()
+
+    expect(result.found).toBe(result.target)
+    expect(result.verdict, 'Compare version must be exact match').toBe(VersionCompareVerdict.ExactMatch)
+  })
+})