The last few days have seen several releases relating to MIME HTML emails. Here's what happened.

The first discovery was that sites which had been sending MIME messages okay before started spitting out error and not sending the mail when their web servers updated to PHP 5.5.26 or later. I investigated and found that PHP version included a change to PHP's mail function restricting what can be sent in the headers field, in an attempt to stop malicious header injections. Unforunately it stopped the MIME code of WSN and many other scripts. I rewrote all the MIME code to use simpler headers and transfered much of it to the message field.

That patch worked for me, but actually created a problem on a PHP 5.4 server which was unable to parse message field headers that used windows-style line breaks. I converted to the PHP_EOL constant and that made all PHP versions work at the same time, finally.

If you have any website which is sending MIME emails by default, please be aware that it either already has or soon will stop sending emails (when you reach PHP 5.5.26) until you update to the latest release of one of the active WSN series: 8.0, 9.0, 9.1 or 9.2.