Is a gem ready for Rails 4 or 5?

Rails 4: 573 ready, 37 not ready, and 436 unknown
Rails 5: 75 ready, 8 not ready, and 963 unknown
Name Status Rails 4 Notes Rails 4 Status Rails 5 Notes Rails 5 Status or notes updated
brakeman ready

Tests show that it works under rails '4.0.0.beta1'.

ready

since gem version 3.1.5

12 months ago
teaspoon ready

_

ready

since version 1.1.5

12 months ago
sass-rails ready

_

ready

since gem version 5.0.5

12 months ago
seed-fu ready

since version 2.3.0

ready

since version 2.3.6

12 months ago
premailer-rails ready

since version 1.3.2

ready

since version 1.9.2

12 months ago
acts-as-taggable-on ready

since version 2.4.1

ready

since version 4.0.0

12 months ago
activerecord-session_store ready

version 0.0.1 is ready

ready

since gem version 1.0.0

12 months ago
default_value_for ready

since gem version 3.0.0

ready

since gem version 3.0.2

12 months ago
redis-rails ready

_

not ready

https://github.com/redis-store/redis-rails/issues/30

12 months ago
rspec-rails ready

apparently full support since gem version 2.14.0 (source)

ready

since version 3.5.0

12 months ago
bullet ready

works

ready

since version 5.2.0

12 months ago
i18n-js ready

since gem version 3.0.0.rc8

ready

with PR https://github.com/fnando/i18n-js/pull/413

12 months ago
action_access ready

Built for Rails >= 4.1

ready

Added explicit support for Rails 5.

about 1 year ago
scenic ready

-

ready

-

about 1 year ago
high_voltage ready

-

ready

since version 3.0

about 1 year ago
factory_girl_rails ready

-

ready

since version 4.4

about 1 year ago
factory_girl ready

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

ready

since version 4.4

about 1 year ago
suspenders ready

-

ready

from version 1.41

about 1 year ago
paperclip ready

since gem version 3.5.1

ready

since version 5

about 1 year ago
clearance ready

from version 1.0.0.rc7 (source)

ready

from version 1.13

about 1 year ago