Hi,
I have oscommerce 2.3.4 running with php 5.6.40, hosted on a linux server. Since beginning of September, I have the following problem: when a client insert non-ASCII characters (mainly Greek letters) in the name field of the contact or order form, I get a base64 encoded Header sent to my email address and an "Undelivered Mail Returned to Sender" in case of order. Since the content is fine, there must be a problem with the MIME header. With ASCII characters, everything's fine. Any ideas?