Is a gem ready for Rails 4 or 5?

Rails 4: 615 ready, 38 not ready, and 433 unknown
Rails 5: 163 ready, 11 not ready, and 912 unknown

Gems ready for Rails 5

Name Status Rails 4 Notes Rails 4 Status Rails 5 Notes Rails 5 Status or notes updated
pronto ready

Does not depend on Rails version.

ready

Does not depend on Rails version.

over 1 year ago
pry-rails ready

-

ready

5.0 from v0.3.3, 5.1 from v0.3.7, 5.2 from v0.3.9, 6.0 (!) from v0.3.9

7 months ago
puma ready

-

ready

default server for Rails

7 months ago
query_optimizer ready

Minimize query for fetching table row

ready

Minimize query for fetching table row

over 3 years ago
rack-attack ready

-

ready

5.1 from v5.1.0, 5.2 from v5.3.0

7 months ago
rack-oauth2 ready

_

ready

since version 1.2.2

about 3 years ago
rails_12factor ready

-

ready

This gem isn't needed for New Rails 5 apps. There is doc in the README for migrating from a Rails 4 to 5 app: https://github.com/heroku/rails_12factor

7 months ago
rails-dom-testing ready

yes

ready

from 2.0.0 https://github.com/rails/rails-dom-testing/releases

almost 3 years ago
rainbow ready

not dependent on rails

ready

not dependent on rails

7 months ago
ranked-model ready

Recent activity and rails4 branch merged in July 3rd. (https://github.com/mixonic/ranked-model)

ready

5.0, 5.1, 5.2 from v 0.4.2

7 months ago
react_on_rails unknown ready

https://github.com/shakacode/react_on_rails/blob/master/CHANGELOG.md#802---2017-06-04

over 1 year ago
react-rails ready

It works in our rails 4.1.6 app.

ready

5.2 from v2.4.5, 5.1 from v2.1.0, 5.0 from v1.7.1 (at least... bugfix for v 5.0 mentioned in changelog)

7 months ago
recurly ready

ready

ready

.

about 2 years ago
redis-namespace ready

Does not depend on Rails.

ready

does not depend on Rails

7 months ago
redis-rails ready

_

ready

since version 5.0.0, see https://github.com/redis-store/redis-rails/blob/master/CHANGELOG.md#500

over 1 year ago
responders ready

since gem version 1.0.0.rc

ready

5.0 from v2.1.1, 5.1/5.2 from v2.4.0

7 months ago
rollbar ready

since version 0.10.3

ready

ready since version v2.10.0

7 months ago
rollout ready

Working with '~> 1.2'

ready

does not depend on Rails

7 months ago
roo ready

Does not depend on Rails

ready

does not depend on Rails

7 months ago
rspec-rails ready

apparently full support since gem version 2.14.0 (source)

ready

since version 3.5.0

about 3 years ago