Details mentioned in the complete change log include fixed dual SIM preference selection issues in settings, added NTFS and exFAT support for OTG, fixed Google Camera photo-sphere and panorama bugs, screen temperature can now be adjusted from quick settings, added hide search bar option in launcher settings, security patches, holiday wallpapers and general bug fixes and optimizations. It will be a gradual rollout process, so be patient if you haven’t received it already!
You can check out the forum thread here for more details, and it is also a good indicator just in case something goes wrong with the latest update, although from the looks of it, nothing of the sort has happened so far – and it looks like it is going to stay that way, too.