Apple released iOS 8.1 update in late October bringing a list of bug fixes for iOS 8 problems, but iOS 8.1 do have its own bugs. After identifying the 7 most common problems after iOS 8.1 update (maybe also for iOS 8.2/8.3/8.4), here I'm to offer corresponding solutions as below.
1. Q: Since I upgraded my iPhone 5S to iOS 8.1, it runs out of power very quickly! Is there anything I can do with it?
A: Battery drain is one of the most common problems you would encounter after iOS upgrade into iOS 8/9/10. But there're 5 tricks you can take to improve the situation.
Navigate to Settings >> General >> Usage >> Battery Usage to see which apps use the most battery life in the last 24 hours and for the last 7 days, then limit the use of them, stop background activity or remove them completely.
Navigate to Settings >> General >> Background App Refresh >> Turn if off for each app that is using too much power to limit background app refresh which drains battery.
Dimming iPhone screen via Settings >> Display & Brightness >> Auto-Brightness >> Toggle On is also an effective way to use less power.
If you find that the usage and standby numbers listed as the same when checking iOS 8.1 battery usage, you need to reset all settings to handle it: Go to Settings >> General >> Reset >> Reset All Settings and then enter you passcode in the pop up windows.
Turn off Bluetooth, Wi-Fi and LTE when you are not using them.
2. Q: Why I can't send files to my friends via AirDrop?
A: In that case, you can simply solve it by pulling up Control Center from the bottom of the screen and change the setting from Off or Contacts Only to Everyone. Alternatively, you can also send large files via WhatsApp.
3. Q: I still failed to send iMessages due to slow connections though I've upgrade my iPhone 5 to iOS 8.1, how to fix it?
A: Slow connection and no connection have plagued Apple users for many years and it seems that there's no different in iOS 8.1. Fortunately, there're 3 tips on it.
If restarting iPhone doesn't work, you can toggle cellular data on and off by navigating to Cellular >> Cellular Data >> Toggle Off.
If neither works, try flipping Airplane Mode on and then flipping it off after 30 seconds or more.
4. Q: Before I updated my iPhone 6 to iOS 8.1, it could get around 50 Mb/s on Wi-Fi. But now it tops out at 25 Mb/s whatever I did. Any solution?
A: We've heard a lot complaint about Wi-Fi issues like erratic connection speeds, Wi-Fi speeds deceleration, etc. Though there's no guaranteed fix for it, reset networking settings might be of great help. All you need is to head to Settings >> General >> Reset >> Reset Network Settings. But note that this would wipe out all the records of your commonly-used Wi-Fi passwords.
5. Q: My iPhone 7 got stuck in a loop of rebooting, how can I solve it?
A: Just like cellular data issues, random reboot also troubles Apple users a lot. So far, there's no way to completely eradicate it, but there're 3 ways to minimize it.
Head to Settings >> General >> Reset >> Reset All Settings.