Grammar check for Mac 10.13 Mail app

Where can I download an old version for Mail?
Thanks in advance!

You can get our desktop app (which supports Apple Mail) here: LanguageTool - Grammar Checker for macOS

This version does not work on macOS 10.13!

10.13 seems to have reached its end-of-life, i.e. it doesn’t get security updates anymore, so we won’t be supporting it. Sorry.