Version 1.7.2 was released to all users on the Google Play Store as the second/final step in patching the Premium purchase bug.
(as of Sept 27, 2018)
Version 1.7.1 was released to all users on the Google Play Store as part of a two step solution to this Premium purchase bug. This version (1.7.1) fixed the purchase error for all new users trying to purchase for the first time using 1.7.1.
We are still working on step two of the solution to be released later this week as version 1.7.2. This version will fix the purchase error for any users who had previously tried to purchase Premium on version 1.7 or below. Those users experienced the bug where they were charged and their account still showed them as Free users. Version 1.7.2 is being built to fix the bug for these users. If you feel you experienced this bug (purchased Premium on Google Play but your account is showing you as Free), please email firstname.lastname@example.org and include the auto-generated receipt of purchase from the Google Play Store.
(as of Sept 25, 2018)
In version 1.7 of the Android app that was released to all users, we found a bug when users try to purchase Premium membership where they are charged but their account remains at the Free member level.
Our engineering team is working on getting a fix out for this ASAP!