I see the same error. Running Linux x64 KSP 0.25. I cannot help but notice that the modification date of NEAR.dll in the release zipfile is Oct 3. And that when I inspect that dll with MonoDevelop, it does not contain the NEAR.PartExtensions namespace. The NEAR.dll I built from the tip of your NEAR github branch does contain the PartExtension namespace (and FARPartExtensions class). It does not trigger the CompatibilityChecker warning. It really looks to me as if an older NEAR.dll is in the release zipfile. EDIT: Nevermind ! Btw, the git tag NEAR_v1.3 points to a commit on the master branch.