Aktualizacja 2.3.5 => 3.0.3

Witam. Po aktualizacji Railsów nie mogę uruchomić serwera:

$ rails server /usr/lib/ruby/1.9.1/rubygems.rb:238:in `activate': can't activate activesupport (= 3.0.3, runtime) for ["railties-3.0.3"], already activated activesupport-2.3.5 for ["rails-2.3.5"] (Gem::LoadError) from /usr/lib/ruby/1.9.1/rubygems.rb:254:in `block in activate' from /usr/lib/ruby/1.9.1/rubygems.rb:253:in `each' from /usr/lib/ruby/1.9.1/rubygems.rb:253:in `activate' from /usr/lib/ruby/1.9.1/rubygems.rb:1119:in `try_activate' from <internal:lib/rubygems/custom_require>:32:in `rescue in require' from <internal:lib/rubygems/custom_require>:29:in `require' from script/rails:6:in `<main>'
Co mogę z tym zrobić?

bundle exec rails server

Albo wyrzuć starą wersję railsów