The first release of the Ruby buildpack after 2020-04-03 will no longer include ruby versions 2.4.x. These ruby versions will no longer be supported upstream. Please migrate your Ruby apps to supported versions of ruby before that time.
Note: As 2.4.x is the current default for the Ruby version in the buildpack, the default Ruby version will be updated to 2.7.x as a part of this removal. If you’d like to use a different Ruby version, please configure your application to select that version.
As always, the buildpacks team is happy to answer questions you may have about this deprecation in the #buildpacks Slack channel.
Kashyap Vedurmudi, CF Buildpacks PM