Through the eShop improvements, the "Download Later" feature now works while the 3DS is in sleep mode with the eShop app open. It also has the ability to conduct software updates in the background.
The North American 3DS firmware update is Version 5.0.0-11U and is currently available for download via a wireless connection.
According to the Nintendo website, system menu versions 5.0.0-0U through 5.0.0-10U will not include new features for the Nintendo 3DS Camera, new content for StreetPass Mii Plaza and system transfer between two Nintendo 3DS systems. These features were included in past system updates but won't be included in the versions mentioned above.
The following, which were included within previous system updates, are not included with System menu versions 5.0.0-0U through 5.0.0-1U: an internet browser, Nintendo eShop and the ability to system transfer from a Nintendo DSi or Nintendo DSi XL system. Again, these additions were made in past system updates but won't be included in versions 5.0.0-0U through 5.0.0-1U.