Apple unveiled the iOS 14 and iPadOS 14 on Monday. Currently, iOS 14 and iPadOS 14 are already pushed out to developers, the public beta is expected to start OTA in July.
However, as before, it's not impossible to OTA upgrade without registering a developer account, deploying the appropriate profile will let you do the upgrade.
After downloading the profile to your device (Safari will tell you to do so), go to Settings - General and install it.
After that, reboot the device and check for updates.
Note that, since the description file installation is not the official recommended method, it is recommended to backup important personal data on your device.
iOS 14 supports iPhone 6s and newer models, iPadOS 14 supports iPad Air 2/3, iPad mini 4/5, iPad 5/6/7, and all iPad Pro.
iOS 14 profile download:
https://pan.baidu.com/s/1F5DG9aWQWYEASRjg0fmr-Q
Code:7eaf
iPadOS 14 profile download:
https://pan.baidu.com/s/1U9cjEyN-m0PiUH9rfRHvnQ
Code:5en7
How to fix this error: Unable To Check For Update while installing iOS 14 / iPadOS 14
This error is most probably related with the jailbreak tool unc0ver, which blocks the iOS auto update feature.
Go to unc0ver. Tap settings on the top left. Uncheck "Disable Auto Updates", then click "Done".
Then turn off your iPhone and turn it back on.
Go to unc0ver again. Jailbreak your iPhone again.
Then reboot and you will be able to start updating to iOS 14.