Patch 1.61 or 1.74?

When I run my Civ4 it says that the build is 1.7.4 or something like that but some sites talk like 1.61 is the latest, and I see the timestamp on the file in the 1.61 zip is newer than 1.74's. What's going on?

1.74 is the last patch for CIV basic program. 1.61 was the patch before that and is included in 1.74. Any site or discussion that indicates 1.61 is the newest is many years out of date. Timestamps on zips don't mean much. That is the date that someone zipped the file, not the creation date of the file itself.

Ok, my next question is: why didn't I get instant e-mail notification when you posted this? I have it set that way, I've double-checked the e-mail address the forum has and I don't see any notice in my inbox or spam folder. Is the forum broken?

The instant email has been malfunctioning for several months. There is a thread about it in the Site Feedback forum, if you want to read about all the problems it has been having and various people's frustration with the malfunction. It includes responses from the Admin and Moderator staff about it.