Gems that may not be rails 4 compatible

rails4gems.md

Gems that need help with Rails 4

• cucumber-rails
• simple_form - has a 3.0.0.rc but it depends on rails 4.0.0.rc1
• delayed_job_active_record - has a v4.0.0.beta3 so likely ready to release soon
• spork-rails - has no indication of even a beta for rails 4
• authlogic: binarylogic/authlogic#368
• activeadmin/activeadmin#1963

active_admin

Active Admin's getting there: activeadmin/activeadmin#2326

Oracle Enhanced

compass-rails

Update:

• delayed job active record 4.0 was released and supports Rails 3.x and 4.0
• spork has an rc and spork-rails has a commit for Rails 4 support, but no official release yet
• @yourwelcome merged some pull requests for authlogic, but there is more work to be done