To make GRASS releases more often and more predictable, here is GRASS next releases feature plan. This feature plan has to be filled by developers working on '''GRASS 6.4'''. 

There is the release branch for 6.4.x - [source:grass/grass/branches/releasebranch_6_4 releasebranch_6_4]. See details at [http://grass.osgeo.org/devel/svntags.php tags and branches]. A release branch is considered as "frozen", only bugfixes can be done.