I've been unable to install Groovy-Eclipse on Spring Tool Suite at least since the beginning of the year. I've tried on release 3.8.3 and now on current 3.8.4, but always get a dependency conflict. This happens on a clean install of STS, with the Groovy-Eclipse install being the first thing I attempt.

I've tried to make sense of what the conflict actually is, but don't really understand it. Interestingly, I have an existing STS install with Groovy-Eclipse installed long ago, and it's able to update both Groovy-Eclipse and STS versions without issue. Not sure if this is a Groovy-Eclipse problem per se, but I'm hoping somebody might have some insight.

I'll attach the error message separately. This is on Windows x64 version of STS.