It seems, OEMs are getting much more stringent towards the security Updates. Recently, Google rolled out the June Security Patch for the Google and Pixel devices. Even, Motorola started the June Security Patch rollout with Android 7.1.1.
The update weighs in around 130 MB in size and it is rolling OTA( Over the Air). Google has fixed some major issues which were listed last month on Google Forums. They have fixed various bugs related to System UI, Radios, etc.
The update is available for unlocked version of the Blackberry PRIV. If you have locked version with any carrier, then you have to wait for the carrier update.
There are many security fixes, than have been added in the June Security patch. So, you can expect, good performance and much secure platform after the update.
Before proceeding for the update make sure your battery is charged more than 50%. Also, you can switch to the WiFi network to save additional charges from carriers.