Why are there different Ruby On Rails versions?

Disclaimer : I am totally new to Ruby on Rails but planning learning it.

This morning I have been reading there were two new Ruby On Rails releases (2.3.11 and 3.0.4).

I don't understand why people (the ROR community)开发者_开发技巧 are working (maintaining) different versions ? What are the benefits for developpers ?

Active development is not being done on the 2.x branch. However, there are lots and lots and lots of deployed 2.x applications in the wild, and given that yesterday's releases were security-related patches, they provided a patch for 2.x users.

Upgrading a Rails application from 2.x to 3.x is not necessarily easy or trivial, and it's unreasonable to expect that as a solution to a security hole, so the 2.3.11 release was made instead.

The benefit is for people who are still using the old version and for some reason does not want to or cannot upgrade to a newer version. It is standard practice that there is some maintenance of old versions.