The phone should have been worth removable batterys. The extent one could actually do a lot of technical stuff with M2 will not he possible with M5.
But one thing is for sure. Gionee is paying hefty sums to useless developers in making stock roms. Uninstall gionee m2 stock rom and put umanh leekha compact darkl rpm which is lollipop based. You will never wish to revert back to gionee m2 stock rom.
But the mobile battery is quit good 4000mah and the mobile is littel bit hevy due to its battery life