[Resolved] PHP Warning: preg_replace(): Unknown modifier 'f' in

Problem:
The client's debug log displayed a PHP warning related to the

preg_replace()

function in the WPML Endpoints Support file, indicating an unknown modifier 'f'.
Solution:
We discovered that the client had translated some non-translatable WooCommerce Endpoints, which was causing the problem. We advised the client to:
1. Not translate non-translatable endpoints.
2. Only translate endpoints that appear in the frontend for users.
3. Remove the incorrect translations of the endpoints from their site.
4. Use hyphens between words when translating Endpoint strings to prevent further issues.
After following these steps, the issue was resolved.

Please note that the solution provided might be outdated or not applicable to your case. If the issue persists, we encourage you to open a new support ticket. We also highly recommend checking the related known issues, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins.