The last stable release (I assume it's Microsoft Certified Hardware) dropped about 22 months ago, while the latest beta version is roughly 15 months old. If youβve been relying on automatic updates, you probably haven't even touched the beta versions. Honestly, the only real difference is the user interface; you get the "crimson" look with the beta, but there isn't any actual performance boost.

Don't sweat it when third-party software flags your drivers as "out of date." Like I mentioned before, these are the final drivers ever released for this specific series, so nothing newer is coming down the pipeline.
By the way, the numbering system is pretty straightforward: the first two digits represent the year, the second number is the month, and the third indicates which driver was released during that month.