Okay, that’s interesting. gem regenerate_binstubs is provided by the executable-hooks gem via rubygems-bundler, which RVM installs by default. That extension should be available to the gem command if it’s the version installed by RVM…
In any case, while we work on a better solution, gem install bundler -v 1.10.6 && gem install rubygems-bundler && gem regenerate_binstubs should make the version of bundler available that you want (it might need to be combined Kim’s suggested echo Y | rvm @global do gem uninstall bundler )