Hello dear WPMU Team,
E-newsletter uses the session_unregister function (in particular, when printing subscribe form markup - e-newsletter.php line 1529, but may in some other places, I'm not sure) - this function is deprecated in PHP 5.3 and is removed in PHP 5.4 (according to PHP.net http://php.net/manual/en/function.session-unregister.php). I use 5.4.4 for local development (that's the latest version of MAMP) and as it could be expected have an'undefined function error. Could you please provide me with some information how to alter the code for it to be compatible with PHP 5.4 and at the same time not to break the plugin logic? Anyway I hope that this information will be in some use for you to have the e-newsletter compatible with future versions of PHP.
With kind regards,