Sony has started pushing stock Android 7.0 Nougat firmware for Xperia X F5121, Xperia X Dual F5122 and Xperia X Compact F5321. Other Sony devices including Xperia X Performance are already update to Google latest firmware last month. The Nougat firmware has a build number updated to version 34.2.A.0.266 and is available as OTA (Over The Air). The stock Nougat OTA for Xperia X and X Compact is released in the selective regions including Latin America, Russia, Australia, Middle East, Turkey, Vietnam and Thailand.
The update is not released at once but will be released in phases so it will not take more time to accommodate all the devices in other regions of the world. Xperia X and X Compact users are going to listen the OTA notification knock anytime soon but you can also check manually, Settings >> About device >> Software updates.
The Android 7.0 Nougat 34.2.A.0.266 firmware is not only the latest version of Android but also it has brought a numerous changes under the hood, like the latest security patch for the ongoing month dates Dec 1 2016, redesigned notification bar, Multi-Window mode, increased stability in over all firmware and much more.
More updates soon!