The new macOS Sierra 10.12 is ready to download and install from the Mac App Store. Before you do the latter, please remember to backup your drive — I suggest two backups at the least. Personally, I always make sure my Time Machine has a fresh backup and I also clone my system drive with Carbon Copy Cloner. Better safe than sorry.
★ macOS Sierra →
P.S. The Dev GM 2 and final build numbers are the same — both are
16A323. The public beta GM is an older build.