We're generally trying to keep up with new language versions as they're released.
The CI tests against the latest JDK EA builds, so e.g. today all of the tests pass on JDK 23.
There may be gaps in support for new features in individual checks. For example there are a handful of checks for issues related to switch statements, and there's been some work to prepare those checks for switch expressions, but I wouldn't be surprised if there are a few more bugs left in that area.
So overall things should just work using Error Prone together with the latest released language version, and bug reports are welcome if you see any issues.