BlackBerry is the first non-Google OEM to push April security patch
Considering the update has just been made available by Google for its Nexus and Pixel devices, alongside Android 7.1.2 Nougat, it looks like a great achievement on BlackBerry's part.
However, it's not the first time that it happens because BlackBerry has much fewer Android smartphones that must receive security updates on a monthly basis.
Besides starting to push the update to its smartphones, BlackBerry published the Android Security Bulletin that contains all the vulnerabilities fixed in this update. Apparently, there are quite a lot of security issues that have been addressed in this patch.
Keep in mind that the update is rolled out OTA, so if you own the BlackBerry PRIV, DTEK50 or DTEK60 smartphones, then you should be notified when April security patch becomes available for download.