Troubleshooting Icons Not Displaying
After applying the WHMCS 7.6 update, the CSS based icons throughout the client and admin areas may not display normally. In place of the expected icon is a small square:
WHMCS version 7.6 uses the newest version of FontAwesome to display icons; FontAwesome 5.
This new version is not backwards compatible with CSS and templates designed for the previous version; FontAwesome 4. As such, icons which no longer exist in Font Awesome 5 will appear as a small square.
Using the auto updater, the stock Six template is updated to use the new Font Awesome 5 icons.
If the update was applied manually, please ensure that all files and sub-folders were uploaded to the /templates/six/ directory, overwriting the existing files.
For users with custom client area templates, the templates must be updated for use with Font Awesome 5.
The required template changes are itemized in the release notes: https://docs.whmcs.com/Version_7.6.0_Release_Notes#Template_Changes
More information on the Font Awesome 5 upgrade are detailed in the corresponding release note: https://docs.whmcs.com/Version_7.6.0_Release_Notes#Font_Awesome_5