Apple released iOS 12.1.3 beta 4 to software developers on Thursday, Jan. 10, just three days after beta 3 came out. Public beta testers also received the update. In general, iOS 12.1.3 fixes a VoiceOver issue with ECG and Irregular Heart Rate notifications, as well as a fix in audio quality on the latest iPad Pro models.
The release notes for iOS 12.1.3 dev beta 4 include the two resolved issues mentioned above. However, just because Apple highlights only a couple bug fixes in its report does not mean that's all 12.1.3 beta 4 has to offer. Presumably, the update is full of minor bug fixes and security patches that aren't mentioned on the surface level release notes. Know that by downloading the beta you are probably filling in quite a few gaps that beta 3 unknowingly contained.
- Resolved an issue where some user interface elements were inaccessible to VoiceOver in the "Electrocardiogram (ECG)" and "Irregular Heart Rhythm Notification" sections in Health > Health Data > Heart. (46505168)
- Audio performance when using some third-party apps is improved on iPad Pro 12.9-inch (3rd generation) and iPad Pro 11-inch models. (46037111)
To download and update your iPhone to iOS 12.1.3 developer beta 4, you will first need to be a registered developer with a valid configuration profile. If you have iOS 12's "Automatic Updates" enabled, you can let the software update overnight. To install now, however, launch the Settings app, select "General," then "Software Update." Tap "Download and Install," then follow the on-screen prompts.
As a whole, 12.1.3 is a pretty minor update for iOS users. In fact, it really feels like an extension of iOS 12.1.2. With that in mind, the main change users have seen in the last couple iOS update cycles is in eSIM fixes for iPhone XS, XS Max, and XR. While users of older iPhones won't be affected, new iPhone users who want to take advantage of this new technology should be excited, as carriers continue to add support for dual SIM capabilities.