[Update: There have been reports of players being unable to access certain network functions on 3DS. Nintendo has acknowledged that, as of 8:19 AM Pacific today, a partial service outage has rendered features like the eShop unavailable. Keep that in mind if you attempt to perform a system update.]
Yesterday, July 7, Nintendo rolled out a new system update for its family of 3DS handhelds, which includes the original 3DS, 3DS XL, and 2DS. The new firmware doesn't introduce anything noticeable — it's a standard stability update, which usually means that Nintendo has quietly added checks to block new hacking methods or streamlined the performance of certain apps like the eShop.
However, what has made several people curious is that the update brings the firmware up to version 8.0.0. Typically, incremental updates are noted by an numerical increase past the decimal, like 7.1.0 or 7.2.0, whereas full version changes indicate much more significant improvements. For comparison, the 7.0.0 update introduced support for Nintendo Network IDs, the 6.0.0 update allowed users to backup save files for downloadable 3DS games and Virtual Console titles to their SD card, the 5.0.0 update brought sleep mode downloading to the eShop and the Save Data Transfer Tool for moving save files from physical games to their download counterparts, and so on.
It's entirely possible that version 8.0.0 is preparation for a much bigger update in the near future. There's speculation that it might even tie into the promised introduction of eShop purchases from other devices like your PC or smartphone. For now, enjoy your "enhanced stability," I guess.