Troubleshooting A non-numeric value encountered Error
Installations running pre-release versions of WHMCS 7.5 (Beta-1 or RC-1) in PHP 7.1 or 7.2 environments may encounter the following error when auto-updating to the stable release designated Release-1:
Error: A non-numeric value encountered
This does not affect users updating straight from 7.4.2 to 7.5 who follow the PHP 7 Migration Guide.
This is due to a PHP 7.1/7.2 incompatibility in the phpseclib validation library. This has been resolved in CORE-12119.
Temporarily switch to PHP 7.0 in order to utilize the automatic updater.
Once you have updated to the General Availability release, you may switch back to PHP 7.1/7.2.