I hope you are well, I just finished this and wanted to post it for everyone to use.
So far I haven't seen any license.php files that were capable of getting automatic updates from WHMCS.
So I decided to do it for you. My license file just needs to be replaced at:
/vendor/whmcs/whmcs-foundation/lib/License.php
The file is located in my github repository (jesussuarz). where I explain everything. It can be used during the installation or after the installation of whmcs.
https://github.com/j...nse-full-update
For some reason no one had done this before, during my research process I discovered that updates are downloaded from bitbutket and can be accessed by anyone as long as WHMCS believes they have a valid license.
If you think this will help you, please give me a star on github.
I hope to contribute with this to the entire community.