CONDSTORE support is now in master.
I have a good start on QRESYNC support, but I may wait until after 0.8.0 to include it.
Any progres on QRESYNC?
Maybe you could put your work in a branch, so people could take a look at your approach.
Unfortunately I didn't push/copy the changes I had made on my old laptop, so I may have to start over. However I think the changes were similar to those needed for CONDSTORE support (e.g. addition of new attributes, flags, etc).
Nevermind, I thought Gmail supported it. It doesn't so now I am looking at Compress support.