If you’re concerned with IP logging on the forum, then you should take a careful read through this thread, where there is a specific section on IP address retention (as well as other info of interest):
https://bitcointalk.org/privacy.php

Pay close attention to the comments on limited retention, since enabling that flag on your profiles reduces the IP info retained substantially (there is a warning that it could make account recovery more difficult in the event, but I figure being able to sign from a posted/quoted bitcoin address should supersede this need).

I’d say though that, if the privacy practices stated are carried out completely, it will be on the running version. Backups may always exist with a snapshot of the data.

Note: Also consider that all external sites that are built around the forum to enhance some functionality or cover the lack off, may also harbour your IP information regardless of the forum’s own policy to that effect.