Device details? As in, operating system and version, cpu, etc. That seems super reasonable for support purposes...
> 2.1.2 Regarding the App: certain data is transmitted by your mobile device: namely your IP address, the periods of time in which you use the App and the type of device you use (e.g. IPhone, IPad), as well as events within the application recorded with Amplitude analytics in order to give us the possibility to continuously improve the App.
From their privacy policy. Oddly enough, no, they don't need to broadcast my ip and when I use the app. Not required at all for me to read PDFs. They may want that data - and if so they should ask me instead of just taking it.
And now that company won't be getting my $80. I'll use the open source alternatives, even if they aren't as nice to use.
Use open source, write your own open source or just do without. You can't just accept the inevitable and bow into it - inevitability doesn't change morality.