The ZTE Axon 7 has had fairly speedy updates - it received Android 7.0 in February, and 7.1.1 in March. The Axon 7 Mini, on the other hand, has been stuck on 6.0.1 Marshmallow this whole time. ZTE started previewing the Mini's Nougat update in March, and it's finally being rolled out to the masses.
The Axon 7 Mini is jumping straight from 6.0.1 to 7.1.1, so you get all the features that 7.0 and 7.1 bring - multi-window, new emojis, app launcher shortcuts, and more. ZTE also says that the update includes support for T-Mobile Wi-Fi calling, so users on T-Mobile can talk and text without needing a strong cellular signal.
To get the update, just tap 'System Update' from the settings app. You can find more information at the source link below.