Where Can i know for which version of ruby is officially tested for a particular version of rails

I have a legacy application of ruby on rails 4.2 and ruby version 2.6. As ruby 2.6 upgrade has reached its end of life, I need to upgrade to ruby 3.1. when I checked rails | RubyGems.org | your community gem host its says only the lower limit. ie ruby version greater 1.9.3 is enough. It did not mention if its supported officially with ruby 3.

but when I tried to rails 4.2 application on ruby 3. It failed . It failed even for ruby 2.7.

So How can i know should I update my rails version or not?

I always refer to this page: Ruby & Rails Compatibility Table - FastRuby.io | Rails Upgrade Service