The new system updates from Apple that were released on Wednesday (here’s everything you need to know about macOS Big Sur 11.5) contain a long list of security fixes, and these have now also come to older versions of macOS.

Apple released overnight security updates of macOS 10.14 Mojave and 10.15 Catalina, reports 9to5Mac.

The updates only contain security fixes – it wouldn’t be expected for Apple to add any new features or design changes at this stage – but there are more than 20 of them. Several of these are important fixes for bugs that have been exploited by hackers and could allow (for example) malicious parties to gain root access to your system.

The fixes apply to a wide variety of parts of the system, from Bluetooth and graphics drivers to the font engine, WebKit and kernel.

Grabbing the new version that applies to the OS you’re using is strongly recommended – and straightforward, too. You simply need to open System Preferences, click on Software Update, wait for your computer to check for updates, and then select Upgrade Now. (Or get to the same destination by clicking on the Apple logo at the top left of the screen, then selecting About This Mac > Software Update.)

If you’d like a little more detail about the process, plus solutions to the possible problems that can occur, here’s how to update macOS on your Mac.

This article originally appeared on Macworld Sweden. Translation and additional reporting by David Price.