@super @truffleruby @eregon That's a really good question! My guess is most pure #RubyLang #RubyGems will work out of the box, but anything with #FFI native extensions might still have issues because it's fundamentally a different #RUBY_ENGINE. #JRuby and others have the same problem, so I don't think that's specific to #TruffleRuby, but maybe there's a plan to solve for that.