Hi,
For non-Premium users, we populate the page when we update the extension to keep you informed on changes we've made and as a reminder to support Adblock Plus if you find the software beneficial. We don't track who has previously paid unless your extension is already upgraded to Adblock Plus Premium (and in that case we won't show you the update page at all).
If you are seeing the update page but you've paid for Premium, please make sure you've unlocked the upgrade on the browser where you are seeing it: https://help.adblockplus.org/hc/en-us/articles/7982499964051-Unlock-Adblock-Plus-Premium
