Is a gem ready for Rails 4 or 5?

Rails 4: 581 ready, 38 not ready, and 435 unknown
Rails 5: 88 ready, 9 not ready, and 957 unknown
Name Status Rails 4 Notes Rails 4 Status Rails 5 Notes Rails 5 Status or notes updated
seed-fu ready

since version 2.3.0

ready

since version 2.3.6

over 1 year ago
premailer-rails ready

since version 1.3.2

ready

since version 1.9.2

over 1 year ago
acts-as-taggable-on ready

since version 2.4.1

ready

since version 4.0.0

over 1 year ago
activerecord-session_store ready

version 0.0.1 is ready

ready

since gem version 1.0.0

over 1 year ago
default_value_for ready

since gem version 3.0.0

ready

since gem version 3.0.2

over 1 year ago
rspec-rails ready

apparently full support since gem version 2.14.0 (source)

ready

since version 3.5.0

over 1 year ago
bullet ready

works

ready

since version 5.2.0

over 1 year ago
action_access ready

Built for Rails >= 4.1

ready

Added explicit support for Rails 5.

almost 2 years ago
scenic ready

-

ready

-

almost 2 years ago
high_voltage ready

-

ready

since version 3.0

almost 2 years ago
factory_girl_rails ready

-

ready

since version 4.4

almost 2 years ago
factory_girl ready

https://github.com/thoughtbot/factory_girl/blob/master/Appraisals#L9

ready

since version 4.4

almost 2 years ago
suspenders ready

-

ready

from version 1.41

almost 2 years ago
paperclip ready

since gem version 3.5.1

ready

since version 5

almost 2 years ago
clearance ready

from version 1.0.0.rc7 (source)

ready

from version 1.13

almost 2 years ago
godmin ready

ok

not ready

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

almost 2 years ago
user_notif ready

It works

ready

It works

almost 2 years ago
devise ready

from gem version 3.0.0

ready

since gem version 4.0.0.

almost 2 years ago
refile ready

Works perfectly

not ready

Not compatible with Rack 2

about 2 years ago
query_optimizer ready

Minimize query for fetching table row

ready

Minimize query for fetching table row

about 2 years ago