The update for my iPhone 13 Pro Max wasn’t very big – coming in at 385MB. Without more details in the changelog than call performance improvements, I don’t expect there to be any other notable tweaks or changes. Maybe some performance and bug fixes that weren’t worth mentioning, but that’s about it. It actually appears that the update is only available for the iPhone 12 and iPhone 13.  I personally haven’t had any issues with dropped calls on the iPhone 12 Pro or my iPhone 13 Pro Max since upgrading. But it’s clear that enough iPhone owners have had issues to prompt Apple to release an update. If you’ve experienced dropped call issues on your iPhone 12 or iPhone 13, give iOS 15.1.1 a try and let us know if you see an improvement in the comments below.