attachment.php in 3.6.5

[RedGTiVR6]

on line 1342 in 3.6.5 it has the following:

$vbulletin->GPC['type']['extension'] = preg_replace('#[^a-z0-9_]#i', '', $vbulletin->GPC['type']['extension']);

In our version (3.6.3) that same line shows:

$vbulletin->GPC['type']['extension'] = str_replace('.', '', $vbulletin->GPC['type']['extension']);

I'm trying to update our forum by following this thread: https://vborg.vbsupport.ru/showthread.php?t=38545

I've gone through the mods on our forum and nothing seems to have touched this template.

I'm wondering a few things:

A) Is this one of the updates that's been made with the new release?

B) Where can I find a list of what all has been updated that might help me as I come across other modifications in the process.

Thanks in advance!