last version of (gem) working with rails 2.3

I want to know what version of a specific gem is working with the last Ruby on Rails 2.3.x (2.3.13 as I am writing) and which one is the last supported officially.

Given a fictional examplegem "Foo" which runs in 开发者_如何学运维version 3beta with rails 2.3 but the development officially support rails 2.3 only until "Foo 2.5" so someone could try to use Foo 3beta but shall not bother the development with bugreports because of incompatibility with rails 2.3

I hope everyone understands my intention, so just edit, comment or answer.

Example: gem "Foo", "~> 2.5" #but "= 3beta" worked for me, see my blogposg at http://example.com/

The List:

• RSpec-Rails: gem "rspec-rails", "~> 1.3"

I use github and find the repository of the gem then check out the tags of different versions viewing the README. A quick google search works as well. I do not know of a resource that gives the information you are requesting.