Many files like /vendor/endroid/qrcode/assets/data/qrv36_2.dat are added. Not sure if they are needed for qr code generation or not.
I've quickly checked in the code and it looks like this code is needed :( might be wrong though. only alternative would be to maybe use another lib. I've simply reused what @sgiehl used for Google Authenticator.
Okay this is a reason:
so -> #13611
Version 2.0 already didn't contain those files anymore. But that requires PHP 5.6. Might be worth to check if that version works with PHP 5.5 as well. Or maybe it's an option to mark the 2FA plugin as compatible with PHP 5.6 or 7 only. So users with older PHP versions can't use it