This roll-out comes with a new Oreo update after the company pulled the original update after discovering a number of bugs.
The new update with the build number OPR1.170623.026.8.1.10 claims to have fixed the bugs that were discovered during the original roll-out. Some of the problems that were discovered after the first roll-out included Bluetooth battery draining issues, random reboots, and unresponsive dialler app, as reported on Mi Community and XDA forums. The report also points out that the company has brought back the fingerprint gestures while removing the SIM HD notification.
Xiaomi has also updated the Android security patch to January 2018.
Apart from that, if you are already upgraded to Oreo, then this new update will be worth 89 MB but if you are still on Android Nougat then you will have to download 1112.4 MB to upgraded your A1 to the latest software version.
The upgrade is rolling out in an incremental manner similar to the previous update. This means that the update will reach Mi A1 users in a phased manner where only a small number of users will get the update. The reason for this is to ensure that no serious last-minute bugs crop up while causing a problem for all A1 users in the market.