5.1.10 has been upgraded to 5.1.12 for some time, but the new 6.0 RC is available to download and it is considered stable with only bug fixes being worked on.
You can find 6.0 RC at the bottom of the download page of your OS hi-lighted in “pink”. It is called “Nightlies” on that page.
6.0 RC installs along side 5.1.12 and is completely independent of 5.1.12 or 10 … even with a different icon on your home page.
The download page can be found at: Help / About Kicad / then click the link to the official website.
Here it is: https://www.kicad.org/