Wiping is for a clean installation... I was reading that data delete apps files, also you should add system, that totally cleans the previous ROM. It's like format and install that is better that simply reinstall.Post #526: I just meant that is recommended to wipe if coming from 7. But of course, you can try installing without wiping before.
https://xiaomi.eu/community/threads/6-6-23.32335/page-27#post-302058
Regarding cache and dalvik are done by ROM during installation.
Inviato dal mio Redmi Note 2 utilizzando Tapatalk