I purchased this garbage app with high hopes. Very disappointed. Do not spend money on it.
After trying this app as well as MiBand Tools, I went with this one because it was packed with more features. I didn't need to purchase PRO, I simply did to support the devs because I was impressed with their work.
Sadly I quickly discovered that most features either don't work or are too unstable to be worth using. The app is buggy as hell to the point where for the longest time I figured it was abandoned.
But today I saw an update adding MiBand 4 support. I downloaded it hoping it would fix the experience. Nope. Edit: You can't download the update through the Google Play Store. Only through their app.
Resyncing the last 15 days on the last version only synced the last 10 days. The update fixed this. I can now sync the last 15 days. On paper at least. The data never actually appears inside the app. Only the last 1 day of steps and the last 4 days of sleep, with one day of sleep missing during those last 4 so basically only 3 days of sleep data is visible.
The only way I was able to make the data re-appear was by using the "Re-calculate" option, which made the last 7 days appear. Everything before that is still missing. Even though I see data from those dates being "parsed" during the sync process, so I know the data is actually on the band.
What's even more interesting is that the heart rate section doesn't have a "Re-calculate" option, but if you click on the graph as far back as a month ago, you get the pop-up telling you what the average heart rate was on that day. Meaning the data is actually there. It's just not visible for some reason.
Not to mention the constantly dropping connection with Google Fit and the need to recreate it. And the fact that settings aren't backed up properly and the manual backup process is a fucking NIGHTMARE and even when you do everything right it still doesn't back up all the settings.
I've already complained about all these things in my review of the app on Google Play that I made shortly after I bought it. In hindsight I should have requested a refund while I could. I just really wanted them to fix the issues. I really wanted to believe they would. 6 months later I'm very disappointed and regretful. They're adding support for new devices without fixing the basic functionality and stability of their app.