@Richard :
From Google:
"AdMob is committed to providing you the most effective monetization solutions. As we innovate, it’s important that we leverage the latest technologies to bolster our platform. As part of this movement, we are deprecating versions 6.4.1 and lower of the Android Google Mobile Ads SDK on September 15th, 2016.
In order to ensure that your ads continue to serve after September 15th, 2016, please upgrade to
Google Mobile Ads SDK 7.0.0 or higher."
I submitted an update using Version 1.99.493 and got the same advisory. You think it's just a generic email to publishers?