Difference between Ruby 1.8.6 and 1.8.7?

Question

What are the main reasons or pros/cons somebody would choose to work in 1.8.6 over 1.8.7 or vice versa?

So far I can only find this answer, which is from the latest version of the Agile Rails beta e-book:

"Rails 3.0 requires requires Ruby version 1.8.7 or Ruby 1.9.2-preview3. (It is known not to work on Ruby versions 1.8.6, Ruby 1.9.1 and preview releases of Ruby 1.9.2 prior to preview3.)"

But my question is not limited to Rails. For example, http://rubyinstaller.org/downloads/ still offers 1.8.6 so presumably there are developers who still need that version over 1.8.7.

Answer 1

http://www.ruby-lang.org/en/news/2008/05/31/ruby-1-8-7-has-been-released/

The new version of Ruby includes many bug fixes, lots of feature enhancements backported from 1.9 and some performance improvements since 1.8.6 while maintaining stability and backward compatibility with the previous release to a high degree. See the bundled documentation for details about compatibility issues.

it seems that the improvements are worthwhile to include, especially since web frameworks have to worry about security a lot.

Answer 2

The 1.8.7 ChangeLog has a list of all the changes in 1.8.7, if none of those changes are important to you then I suppose you could stay on 1.8.6...