Ok I don't know much about cgi or ubb code but the calendar hack just caused me major grief. Who knows, maybe I didn't something wrong I don't know but this was what happened and maybe someone can use this to avoid the same problem.
I had a bunch of hacks on the board. Namely, font glow/color, avatars, custom ranks, memberlist and sticky threads, along with the calendar hack. As usual the board crashed. Not sure why and it really doesn't matter because UBB crashes all the time for me. Even with no hacks. So I figured I'd just reinstall the newest version. Well that is when everything went wrong. I kept getting errors saying that hack attempt was logged and something about extra fields in the member files. Turns out it was referring to the field that is added by the calendar hack. It's the last field in the member file and UBB without the calendar hack installed does not like this.
So I had to go into every member file and delete this last line. I have 1400 members. Luckily I had about 900 backed up. But everyones post count, password and all was put back. A lot of people don't like that. Anyway, it just took a long time to get this done.
All the other hacks do not interfere with the board if the hack is not installed. They don't create new lines in the member file, they just use blank lines. Many times I'd just upgrade with no hacks and then install the hacks one by one to make sure it works fine. As each hack is installed the feaures are activated and are like they always were from the member file.
I think the calendar hack is an awesome hack but with that extra line it will cause havoc for some people upgrading. If there is a better way to do this and to avoid it let me know because I'd love to keep this feature on my site.
Mike