Ruby 1.8.7 retires as planned
If Ruby developers aren't using Ruby 1.9.x or 2.0.0, they should be looking to upgrade as Ruby 1.8.7 has now reached its official end of life. The end of life is far from unexpected; the announcement of the planned retirement came in October 2011 and in June 2012, Ruby 1.8.7 moved into security fix only mode.
Ruby 1.8 was introduced in August 2003, built in C and using a single pass interpreter; more recent versions of Ruby have moved on to use YARV, a bytecode interpreter. Ruby 1.8 was, though, the version of Ruby in use when Rails became popular and in turn established Ruby as one of the more popular programming languages available. In June 2008, the release of Ruby 1.8.7 built on the established version of Ruby and included some features backported from Ruby 1.9 which had arrived in 2007. Ruby 1.8.7 has been maintained since then as the last of the Ruby 1.8.x branch, a branch which is now completely unsupported by the Ruby developers.
Ruby 1.9.3 is the oldest, "nearest" release of Ruby to 1.8.7 that is actively supported. Ruby 2.0.0 is the newest version, having been published in February 2013. The H Developer has a feature article Ruby 2.0 - the 20th birthday present with further background on this release.