One of the most frequently asked questions I hear is this one: "Should I install updates on my phone as soon as possible, or wait?" Answer: Sometimes it's best to wait a few days to see if other users report any problems.
In some cases though, you should install updates ASAP and this is one of those times for Apple devices.
Apple updated it's iOS to 13.4 a couple of weeks ago and almost immediately people started reporting problems. Then Apple released 13.5 and people reported it drained the battery. Other users claimed iPads wouldn't reboot and there were problems playing MP4 videos.
Then, three days later Apple released an update to the update: iOS 13.5.1. You might think it addressed those issues but according to those Apple users, it did not.
Some iPhone X and 11 users say the update causes a green tint to appear sometimes on the home screen. So what did it do? Apple isn't specific when it releases important security updates as it might tip off hackers and malware writers, but Apple did say with this update that it had bug fixes and other security updates along with an explanation that it would allow "kernel privileges."
It's not unusual that Apple releases an update so close to the previous update, but when it happens it's usually a serious security issue. That's the case here. It's called a Zero-Day exploit and allows malware to access the operating system so a hacker can do pretty much what they want to do on the phone or device.
The latest iOS update then is 13.5.1, the latest version for macOS is 10.15.5, the latest version of tvOS is 13.4.6 and the latest version for the Apple Watch is 6.2.6.
Check your settings in the About section to make sure your device is running the latest update and if not, install the update soon. You might also see a red "1" next to the settings icon. If you have automatic updates switched on, your device may have already updated the OS.
I do not suggest enabling automatic updates because I think it's best to let other people try it and find the bugs ahead of me. In this case though, you don't need to wait.