Is a gem ready for Rails 4 or 5?

Rails 4: 614 ready, 38 not ready, and 433 unknown
Rails 5: 158 ready, 12 not ready, and 915 unknown

Gems not ready for Rails 5

Name Status Rails 4 Notes Rails 4 Status Rails 5 Notes Rails 5 Status or notes updated
activerecord-postgresql-extensions not ready

https://github.com/dark-panda/activerecord-postgresql-extensions/issues/5

not ready

https://github.com/dark-panda/activerecord-postgresql-extensions/issues/9

11 months ago
dynamic_form not ready

See Leslie's comment below

not ready

See Leslie's comment below

about 3 years ago
godmin ready

ok

not ready

https://github.com/varvet/godmin/issues/193

over 2 years ago
grouped_validations not ready

https://github.com/adzap/grouped_validations/issues/11

not ready

Not ready for Rails 4

8 months ago
heroku_rails_deflate ready

https://github.com/mattolson/heroku_rails_deflate/issues/13

not ready

https://github.com/mattolson/heroku_rails_deflate/pull/24 ; https://github.com/mattolson/heroku_rails_deflate/issues/26#issuecomment-360893277

about 1 month ago
quiet_assets ready

-

not ready

See https://github.com/evrone/quiet_assets#deprecation

29 days ago
refile ready

Works perfectly

not ready

Not compatible with Rack 2

almost 3 years ago
shoulda-matchers ready

ready since gem version 2.4.0 (source)

not ready

will be ready in version 4.0, see https://git.io/vplw7

10 months ago
socialization ready

since version 1.0.1

not ready

-

almost 2 years ago
squeel ready

Support for ActiveRecord 4.0.0 added in version 1.1.0 (source)

not ready

see https://github.com/activerecord-hackery/squeel/issues/412

over 2 years ago
validates_timeliness ready

Since version 4.0, see https://github.com/adzap/validates_timeliness/blob/master/CHANGELOG.rdoc#400-2015-12-29

not ready

see https://github.com/adzap/validates_timeliness/issues/143

almost 2 years ago
workflow ready

since gem version 1.1.0

not ready

see README

over 1 year ago