ZTE

I purchased the phone Avid 2 month ago, but recently the speed is a little bit slow. I came to ZTE official website yesterday, and downloaded one sd card upgrade package which I didn't find out before, I really surprisingly find out the problems can be solved more. Now my phone is working smoothly, and speed improved a lot!!! Perhaps I once intalled too many apps in my phone which caused this issues?Is it update tool package that assist me? 😳