Samsung has started rolling out a new update for the Galaxy Note 5 in India which includes May security patch. The OTA update weighs in at about 359.77MB and the changelog here is quite generic saying that it offers device stability, new or enhanced features as well as performance improvements. The build number of the update is N920GDDU2BPD3.
Given the large size of the update there are bound to be some bug fixes here as well. You can check for updates by going into settings if you haven't received the notification yet.
The Galaxy Note 4 had earlier received the same update with May security patch.