Huawei Mate SE Oreo update is now rolling out by Huawei officially and it is very large. It will update your smartphone to version BND-L34 22.214.171.1240 (C567CUSTC567D4) and load tons of new Huawei-made features on phone. The notification bar is smarter with EMUI 8.0, you can quickly use most-used operations now. Settings menu has received good changes to modify your experience a little more. Interestingly, AI optimized improvements are included that can enhance the speed of phone a lot.
As I just said, the update for Mate SE (better known as Honor 7X) is very large, it is 2.39GB in size. So you should be connected to Wi-Fi instead of mobile data connection as it can hurt your monthly plan. As far I know, many users are going to jump from EMUI 5.1 to EMUI 8.0 based on Android 8.0 Oreo.
You can download Mate SE Oreo update to install manually too, from here.