Apple is now rolling out the official version of iOS 12.1.3 to iOS devices, the full upgrade firmware size is about 2.6GB, the firmware size of different devices is different. This upgrade includes a bug fix for the iPhone or iPad. In addition to the OTA upgrade, users can also upgrade through iTunes by downloading the full firmware.
The specific updates are as follows:
Fixed an issue that could affect the scrolling of photos under the “Details” view of “Information”
Resolved an issue where streaks might appear after a photo was sent via a shared form
Fixed an issue that could affect cellular mobile network connectivity when using dual SIM cards
Fixed an issue that could cause audio distortion when using an external audio input device with the iPad Pro (2018)
Resolved an issue that could cause some CarPlay in-vehicle systems to disconnect from iPhone XR, iPhone XS, and iPhone XS Max
In addition, this update also includes iPod bug fixes, fixes that may cause iPod to restart, and resolve issues that may cause Siri to stop listening.