LMDB master branch

[opensource@gmx-topmail.de]

Hi there,
 
I am on the mdb.master branch because of MDB_VL32. We updated the LMDB code in January, and before I update to the latest commit I wanted to check with you.
 
Disclaimer: I am aware of being outside of the official release cycles and potential risks. On the other hand, we have a lot of unit tests, and a pretty good installation base. In that way it is also a good test for LMDB.

Now to my questions:
1) What are your rough plans with mdb.master in terms of time line and features?
   (With the 0.9.20 release being delayed, new features may pile up in mdb.master. When will they be merged?)
2) Is mdb.master running on any systems you know of? 
3) Recent changes in mdb.master also include format changes for the locking file (e.g. commit "Store lock ID instead of pathname in lockfile"). What are the consequences when updating from an older version?
4) Are the formats for lock & data files considered stable?

Thanks,
Markus