@BraveSauce any chance you are setting a userId in the image tracking method? As we changed there something in a recent release around that. It might not be PHP 7.4 related

@tsteur As a matter of fact, I do use uid in the tracking method. I tried to play with _id values paired with my uid to fix this issue but it breaks my c_n values if I use it.

Edit: Looking at my logs this might indeed not be php7.4 related, sorry for the wrong information. Looks like it started hapenning mid November. Any suggestions on how to get the old functionality back?

Do you know if you have maybe trust_visitors_cookies enabled in your config/config.ini.php file?

You mention the solution already basically ideally you would set _id to some 16 characters hexadecimal string. You could for example hash the userId to generate a visitorId for each user. I can't really think of any reasons this could break your c_n values unless you values are not properly URL escaped.

For closure, just wanted to report that this issue was fixed in later beta updates without any code changes on my end.

Awesome thanks for letting us know @BraveSauce