If you run any version of IPB, there has been a new security hole discovered. The ssi.php file can be SQL injected remotely allowing a cracker to gain access to the passwords (kind of a backdoor into the admin cp). The ssi.php file is only needed if you are integrating with a website (kind of like an RSS feed) and has no effect to the rest of the board if removed or renamed. I have an online friend whose forum was taken down by a cracker and when he finally got the site back up (all of the admin/mod passwords had been changed), it was taken back down again very quickly. Through the process of elimination, they discovered the problem with the ssi.php file (incidentally, a while back, it was announced that there was a problem with the ssi.php file, but it was considered to be minor). Invision worked with the webmaster of the site and they do know about the problem, so probably either expect a new security patch on the horizon or just the advice to remove/rename the ssi.php file.