Ads on system apps? I dont think so. Check carefully it might be some other app. and switching back to windows phone? For real!!!After having 3 Redmi phones i think i finally have enough.
Once i had Redmi 3S, Redmi 4X, then Redmi 5 Plus. I don't think i will buy a new one and here's why.
1) Well, they had great specs for their price, but they compromise durability by using cheap, weak and low-series aluminum to make their phones. That's why Mi5 and Redmi Note 3 failed Jerry's durability test. Basically, these are one drop phones. Europe is used to durable phones like Nokia, LG or Sony.
2) Software. MIUI 8 was great, had alot of features and MIUI 9 made things faster, but... My annoyance level is similar to dealing with Meizu phones. Some themes make unwanted changes to my home screen layout. Messenger notifications are quiet, just silent pop sound instead of normal messenger sound when screen is locked and off. On Redmi 5 Plus i had YouTube issue, where video as well as whole UI was freezing sometimes. This was ridiculous.
3) Ads ! Ads everywhere ! They started pop up in system apps such as Music, Videos , Themes and Settings after MIUI 9 update. Xiaomi, are you serious ? That is definitely unacceptable.
4) After MIUI 9.5 update themes app disappeard from my phone. To restore it, i had to change region to United States.
I switched back to Windows Phone.