Bundler versions 2.4.22 and 2.5.6 are now available for Ruby Applications

[schneems]

Prior https://github.com/heroku/heroku-buildpack-ruby/pull/1427 Closing https://github.com/heroku/heroku-buildpack-ruby/issues/1408

The Ruby Buildpack now installs a version of bundler based on the major and minor version listed in the Gemfile.lock under the BUNDLED WITH key. Previously, it only used the major version. Now, this logic will be used:

• BUNDLED WITH 1.x will receive bundler 1.17.3
• BUNDLED WITH 2.0.x to 2.3.x will receive bundler 2.3.25
• BUNDLED WITH 2.4.x will receive bundler 2.4.22
• BUNDLED WITH 2.5.x and above will receive bundler 2.5.6

It is strongly recommended that you have both a RUBY VERSION and BUNDLED WITH version listed in your Gemfile.lock. If you do not have those values, you can generate them and commit them to git:

$ bundle update --ruby
$ git add Gemfile.lock
$ git commit -m "Update Gemfile.lock"

Applications without these values specified in the Gemfile.lock may break unexpectedly when the defaults change.