Apple has just released iOS 12.3 Beta 3 for iPhones. Comparing with the previous version, the iOS 12.3 Beta 3 is actually a minor update to fix several unseen bugs. For example, it has fixed an issue that may occur while changing the system time of the device using Japanese as the language and calendar.

If you want to upgrade to this version:

Step 1 Connect your iDevice to PC with a USB cable and launch 3uTools.

Step 2 Navigate to Flash & JB → Easy Flash and select iOS 12.3 beta3. After you click Flash, there will be a popup reminder and please read it with caution. If you want to save your data, please check the box "Retain User's Data While Flashing".

Please back up your iDevice regularly just in case.

Step 3 Keep a good connection and internet while flashing, wait patiently for around 5 to 10 minutes. Your device will be restored to iOS 12.3 Beta 3 after reboot.