LMDB 1.0 is out, with some great improvements!
However, you should not upgrade blindly. The on-disk format is not compatible (opening 0.9 databases with 1.0 yields "File is not an LMDB file", which has already scared one PowerDNS user), and some programs (Postfix, Knot) have noticed that they needed to adjust API usage here and there.
Upgrade info/guide: http://www.lmdb.tech/doc/upgrading.html
A warning about blindly upgrading: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=296530
So, enjoy LMDB 1.0 - responsibly!