Double crosspost to wikipedia-l and wikitech-l because this might affect some people.

There was a bug with history paging whereby the last item of one page was displayed as the first item of the next, i.e. the pages overlapped. This has now been fixed in MediaWiki, and the fix will shortly be live on Wikimedia sites. The consequence of this is that some history URLs will now be offset by one row compared to how they were before. A link like this:

http://en.wikipedia.org/w/index.php?title=Main_Page&offset=2006032000443...

...will display the items *after* 2006-03-20, 00:44:34 UTC, *not* inclusive of that date, whereas before the fix it would have displayed items inclusive of that date.

The reason for the change is that if we kept the same URL scheme, in some cases, it would have required an extra database query to work out the correct offsets for the prev/next links. Using non-inclusive offsets, all the data is available already.

-- Tim Starling