If your camera firmware version doesn't match the required one:
On https://builds.magiclantern.fm, next to your selected build you will find Required Canon firmware version with a firmware update file name listed. Grab that file name, go to https://eoscard.pel.hu and there you can download the file.
Now you can use it to update (or downgrade) your device to required firmware.
For downgrading, you may want to read How to downgrade Canon firmware
Because there is no software development support for Magic Lantern by Canon we are forced to use very specific firmware versions with a dedicated Magic Lantern version for your cam.
Magic Lantern will not install or run on your camera if the versions don't match!
And because adaption to a newer Canon firmware version means a lot of work from our side we may just hang to an older version.
In short: to make ML installation work you may have to update or downgrade your cams firmware version!
But Canon often offers download links to newest firmware versions only and not to older ones. Causing troubles locating required versions. Therefore we link Canon firmware files located outside of Magic Lantern project: On a server maintained by a long time supporter named Pelican.
Access https://eoscard.pel.hu and scroll down to the box for your cam.
If you have doubts about reliability/trustworthyness: Pelican programmed EOScard utility more than 13 years ago and we relied heavily on it and still recommend using it for troubleshooting and other things. We are thankful for the services he provides for free.
MacOS and Linux users can download the file and use any file archiver to unpack this “exe”. It is a so called “self-extracting archive” and not a Windows program/app