We tested with 1.9 a while ago and ended up going with a different product because of some workflow issues. The 1.10 branch seems to have those issues resolved but there seem to be a lot of small bugs in it that makes it unsuitable for a production environment. Wasn't sure if I was just missing something (the v1.10-RC.2 branch notes in Github are under 1.8, wasn't sure if there was somewhere else for subsequent releases).