New SteamOS makes Steam Deck a better machine with bug fixes, microSD improvements, and even 'improved battery life by up to 10%' in some situations

pcgamer.com:

The Steam Deck has been one of the best handheld gaming PCs basically ever since it launched yet finding a rogue software problem isn't unheard of. Valve has put out a new OS update that may just make the whole handheld a little better and squash a whole heap of bugs. 

SteamOS 3.6.19 has just launched and Valve put out notes on what it has changed. As well as fixing a whole host of issues like «the frame limiter not properly applying in certain situations» or «a rare issue where sound output could be corrupted on certain boots», it also improves general stability and comes with quality-of-life fixes. 

Interestingly, this update is said to improve the speed of future OS updates and even improves the «reliability of certain microSD card usage scenarios». This includes finding a problem where some SanDisk microSD cards were not picked up by the device.  

If you happen to use your deck for non-gaming things, like light browsing, you will get a big bump from this update as the LCD Steam Deck got «Improved battery life by up to 10% in light load situations», as well as overclocking controls. The Steam Deck OLED, already having a superior battery life, has caught up with the LCD by now getting support for Windows Bluetooth driver. 

If you want to get the latest version of SteamOS on your Steam Deck, it should automatically happen when plugged in and in sleep mode but you can also prompt your device to update. Simply go into 'Settings', then into 'System', and click the button to check for any updates. If it detects an update, you can simply prompt it to download and install it. 

If you don't see the update here, check your internet connection and make sure it hasn't automatically downloaded for you. 

Once downloaded, your Steam Deck will be a lot better in very small ways. Unless you've been met with specific bugs that have been fixed this time, you likely won't notice changes immediately but it should lead to a smoother experience, which is what all the best OS updates