Apple on Tuesday issued new betas for those in the public testing program. The same first betas of iOS 12.1.2, tvOS 12.1.2 and macOS 10.14.3 that were released to developers yesterday, can now be installed by public testers using their respective OTA mechanisms.
These updates are largely expected to feature under-the-hood improvements, rather than new user-facing features. Apple says as much in the release notes for iOS 12.1.2: “contains bug fixes and improvements,” and we didn’t come across any major changes in yesterday’s betas.
Nevertheless, we are installing today’s public betas and will be sure to report back if we find anything noteworthy. You can flash it using 3uTools , don't forget to choose to "retain user's data".
Source: idb