plugins not working on trunk (2.6.3 vs 2.7.0)

Hey guys I tried to compiled my own version of spark from the repo but looks like core still using 2.6.3 and the plugins (spellchecker) requiere 2.7.x

1. how can I get the 2.7.x branch? (don't seem to be out yet).

or

Any suggestions on how to get the spellchecker plugin to work on the lastest trunk ?

Thanks