Seems either their latest update broke the back end or they haven’t paid their bills in a while for their server hosting. I continually get “Service interface could not be activated” even after a full reinstall.

The quality of the Power2max itself is not in question. The app, which is an important partner to the power meter, lends you to believe otherwise. The app works, but 1st do yourself a huge favor and register through the app-portal, not the app itself. The app and the Power2max website have the app-portal pass through. Once you register yourself, you can register your power meter. Then login to the app with your email and password you registered with on the app-portal. I did this and it worked. I was able to update my firmware and even register another power meter. The app seems to work fine now, and though both firmware updates stalled at times, I just killed the app and started over. Also the iPad app seems better than the iPhone app, but the iPhone did install the updates. Good luck.

So many of the other posted reviews are correct, but the app isn’t as bad as they may lead you to believe.- There are few instructions on the app. Would like to see something like “turn your chain crank to activate the power meter” or something… Does not connect to the meter reliably- Why does the app keep telling me I just updated the firmware when that upgrade happened over twenty four hours ago?- Registering an account using the app is very difficult. Bad entry field prioritization, you will need to start the app multiple times, just so amateurishly designed.- Purchasing upgrades doesn’t seem to work on iOS once the app takes you to the web site/portal. I had to log in using a computer’s web browser (Firefox) and even then the upgrade store worked like it was written by a ten year oldFor such a great power meter, their app and web site is so childishly written/designed.

Confirmed app works as expected on iPad mini 14 iOS 15.6.1.I was able to create an account, activate Bluetooth, connect to powermeter and update firmware (no current firmware update on my device).Rating 3 stars because this device iOS combo is likely not easily accessible by most users. App functioned as expected on this device though.