File upload stopped working when upgrade to php 7.2

Hi – I have a file upload field on a form that was working then updated my server to php 7.2 and now form will not upload any files. No error messages in log file either. Get the success message and everything looks good but file is not uploaded or attached to email.

Changed back to php 5.6 and the uploads started working again.
Any ideas what needs to be done to fix this?

Thanks!