Release date: Dec 14th 2011
We recommend all users of 1.6.x upgrade to this version. The 1.6.4 database is compatible with v1.6.0/1.6.1/1.6.2/1.6.3, so rolling back your installation in the case of errors is trivial.
OpenMRS 1.6.4 represents build OpenMRS 126.96.36.19957
These modules are bundled with the 1.6.3 openmrs.war. They will be started automatically and can be removed if they are not wanted.
Also see all tickets closed against 1.6.4: https://tickets.openmrs.org/browse/TRUNK/fixforversion/13512