Update release notes

ReleaseNotes.txt

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+Release notes v.2.3.9
+
+- LevelDB option for blockchain storage. The 'DB' folder is renamed to 'RocksDB', existing folder has to be renamed manually upon upgrade to this version. Use default DB config in Payment Gate Service.
+- RPC: add current max block cumulative size to `/getinfo`
+- RPC: Handle request to check proof of funds that didn't exist yet at given height
+- RPC: Fix transaction details timestamp in `gettransaction`
+- Add `--scan-height` param to walletd startup options
+- Display include folder as separate part of project in Visual Studio's Solution Explorer
+- Move DNS checkpoints host to config
+- Get wallet outputs and ability to manually select them for sending
+- Changed block index to height in response of `queryblockslite`
+
+Release notes v.2.3.8
+
+- Option to save raw transactions to file without broadcasting to the network
+- Protocol: drop the connection if failed to request missing objects in handle_response_chain_entry
+- Changed blockchain rewind implementation
+- Changes in allowed and disallowed busy Core EPC endpoints
+- Fixed incorrect pending balance shown in wallet in some edge cases
+- Revert "New output selection for transaction sending - 'smart' input ordering using buckets" as it has an unpredicted impact on traceability of transactions
+
 Release notes v.2.3.7
 
 - Some bandwidth saving in the exchange of peer lists