Apple released iOS 12.4.1 on Monday, a security release that, “provides important security and stability updates, and is recommended for all users.” Apple has not yet published the separate security patch notes that usually accompany such releases.
The update is available now through Software Update on iPhone and iPad. It’s a 102.6MB download as an over-the-air update on iPhone XS.
After the update I had problems with my iPhone. It wouldn’t synch with my Apple Watch, Podcasts I was listening to were stopping and starting, the camera screen was hard to describe with several windows and bars. I did a forced restart and it now seems fine.