Everybody will get this security alert... and yes MoPub needs to be updated to the latest sdk. I don't even use mopub, it would be nice to compile the sdk's from builder page only with the ad sdk's used by user (admob by default and the rest only if the user want to use them) - but that's just a dream
Your app(s) listed at the end of this email utilize a version of the ad platform MoPub that contains a security vulnerability. If you have more than 20 affected apps in your account, please check the Developer Console for a full list.
Please migrate your app(s) to MoPub v4.4.0 or higher as soon as possible and increment the version number of the upgraded APK. Beginning July 11, 2016, Google Play will block publishing of any new apps or updates that use pre-4.4.0 versions of MoPub.
Affected App(s) and Version(s):