iOS 11 is in 10.01% of compatible devices 24 hours after its release, a figure that has dropped significantly compared to the releases of previous versions of iOS. If you have upgraded without waiting to see the feedback from other users and see that your device does not work as it should, you may want to go back to iOS 10.3.3 before Apple stops signing it and waiting for it to launch the first update of iOS 11, in the hope that it will solve issues in you devices.
Keep in mind that if you do not have a clean installation, ie from scratch, erasing all the contents from our iPhone, all files accumulated in your device can affect the performance. With that said, make sure before running back to the previous version of iOS that Apple is still signing, you should take into consideration that a fresh install is better. But if there is no way to improve the performance then it is probably better that you go back to iOS 10.3.3
How to get back to iOS 10.3.3 from iOS 11
First, make sure to turn off Find my iPhone by going to Settings > iCloud > Find My iPhone, then go to our download page and download the version of iOS 10.3.3 corresponding to the device in which we want to install it. This file will have an ipsw extension and will occupy slightly more than 2GB, depending on the target device.
Then we go to iTunes and connect our device to the Mac or PC.
- Go to the icon that represents the connected device located in iTunes
- On the right side of the screen , click Search update with the following key combination:
For Mac users : press this option with the Option key pressed.
For Windows users: press the Shift key while clicking on Check for updates.
- Then a window will open, select the file ipsw downloaded to begin the process of restoration.