On March 1, Microsoft released a Cumulative Update to Windows 10 1511, a k a, the November update. This update, also known as version 10586.122 (as well as KB3140743), is not an Insider preview; it's a set of fixes for the shipping version of Windows 10 for PCs and tablets.
Among the changes in 10586.122 for Windows 10 PCs are improved reliability across the board; improved device support; improvements in Cortana voice quality and translation and more. The change list as to what's new is available from Microsoft on its Windows 10 Update History page.
Like the 10586.122 build for Windows 10 PCs, this is a Cumulative Update with a number of fixes and performance improvements. (It's a "Threshold" update, not a "Redstone" one.) On phones, these improvements included improved Internet Sharing; improved data connection profiles for dual SIM devices; improved video recording capabilities and more.
The 10586.122 preview build will work on four additional new devices: the MCJ Madosma Q501, BLU Win HD 510U, BLU Win HD LTE X150Q and Alcatel OneTouch Fierce XL.
Insiders who are on the Fast Ring might need to temporarily switch to the Slow or Release Preview rings to get this build, Microsoft officials said.