When looking in the 7.6.0 code when I find something I always compair to 7.5.9 code to see what changes where made. If there is an issue and the code is the same I then look back at 7.5.8 and even 7.5.7 pretty much the reason I had stated I think once that the bug or error was back an issue or so.
Any program that has been around a long time and new versions or additions are never started from scratch on a newer rewrite their for sometimes bugs may be present in several versions in areas not so well traveled. Over 80% of all code is recycled in every software and program I have ever seen or written my self, if not there would never be new software releases. I have been coding since 1982 so I speak from experience.
I see your reasoning for UTC in UBB.threads however I still see revelance of the server time too. Even though this is a internationally used product a local website operator would still like to see the server time in the control panel for various reasons especially if his server is sitting only a few feet away from him or her. I'm not saying base the entire software in one or the other but at least have it display on the administrative dashboard for reference as his or her server time may be off for some odd reason. I have had issues with my own servers once in a while as to where my server(s) and it time based systems became off by an hour for unknown reasons even after having my stuff polling NTP Servers.
Now think about that if you have an intrusion issue and you will need to review the server logs themselves and your looking for a log entry of 23:31 20160504 and your server is off and the server log is showing it as 00:31 20160505 as not all countries utilize the spring forward or fall back and your NTP server is not selecting the proper time season for some odd reason as it is polling a time server in a different time zone. That could create an issue. It has for me when a trusted person ripped off my database and my times didn't match from the software log to the server log.
