Code coverage for Ruby 1.9 with a powerful configuration library and automatic merging of coverage across test suites.
Rails LTS provides security patches for old versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2)
Note that rcov won't ever have support for Ruby 1.9, you're supposed to use rcov for 1.8 and simplecov for 1.9.