EPUB 2.0.1 is a maintenance release of EPUB 2. Its development was chartered in 2009, and the final standard was approved by the IDPF Membership as a Recommended Specification in May, 2010.
EPUB 2.0.1 was superseded by EPUB 3.0 in October, 2011. As of June 2014 the latest released version of EPUB is EPUB 3.0.1. EPUB 2.x is now considered obsolete and is no longer under active maintenance.