How to Use WHMCS license :
Download License.php file from client area of licencepro
and replace it with YOUR-WHMCS-PATH/vendor/whmcs/whmcs-foundation/lib/License.php
How to Update the whmcs :
1: Update with the Automatic Updater
2: Updating WHMCS Manually in the Browser
Known Errors Solution:
1: License error page after upgrade WHMCS : if You see license error page after update or upgrade of whmcs please follow below solution:
Download License.php file from client area of licencepro.net
and replace it with YOUR-WHMCS-PATH/vendor/whmcs/whmcs-foundation/lib/License.php
2: How to Upgrade PHP for WHMCS upgrade Using cPanel MultiPHP
Follow the link : https://help.whmcs.com/m/updating/l/1309170-how-to-upgrade-php-for-whmcs-using-cpanel-multiphp
