This is odd. Canary (after the change I cited) is the one way to go version 12. If you like, you can look at some destination file, decrypt if it has a .aes extension (in AES Crypt or Duplicati SharpAESCrypt.exe), unzip to get the manifest file, and it will say what Duplicati version made it. Here’s one from my Canary:
{“Version”:2,“Created”:“20230106T221149Z”,“Encoding”:“utf8”,“Blocksize”:102400,“BlockHash”:“SHA256”,“FileHash”:“SHA256”,“AppVersion”:“2.0.6.104”}
GUI About screen also shows it (as do other methods), but that requires a system still running Duplicati.
You can read C:\Program Files\Duplicati 2\changelog.txt, but that’s the original before updates. Possibly you can go there to run Duplicati.CommandLine.exe help system-info to get its Version name and Base install folder and Current version folder. For static files, you can look at these: