I'm looking for a mapping between PUMA codes (Public Use Microdata Area from the American Community Survey) to county. UMichigan has this mapping (linked from this), but there's no date so I'm not sure if it's still relevant.
According to the US Census Bureau, "State partners define PUMAs once a decade after the decennial census." The most recent census was in 2010, so the current PUMA crosswalk would be the one based on the 2010 census.
UMichigan has this crosswalk on their website, which appears to the the same as the one you linked to, although the URL is different. I got to it from this page. Based on the fact that it says "2010" on that page, I would expect that this is the 2010 crosswalk. You might want to you contact them and inquire, just to be sure.
They also provide historical PUMA Equivalency Files for 1980, 1990 and 2000.