I have installed DavDROID 1.9.5-ose on a Xiaomi Redmi Note 4 with MIUI 9 which is basically Android 7.0.
I have previously installed the same version on several LineageOS 14.1 phones.
On the LineageOS phones, everything works as expected. After configuring my OwnCloud server account in DavDROID I see my CalDAV calendars in various calendar apps such as Google Calendar. I also see my CardDAV contact in the Google Contacts app.
Following the exact same steps on the Xiaomi phone though the configured CalDAV calendars are not showing up in any calendar apps including Google Calendar. Either are contacts showing up.
Looking in DavDROID’s Debug info I can see that {READ,WRITE}_{CONTACTS,CALENDAR} have all been granted.
Any ideas why none of these are being seen by the Xiaomi phone?
Yes it has been discussed various times in the forum and the solution is also found in our FAQ section 
Xiaomi did some (questionable?) branding with their Android version…
Here we go: https://www.davdroid.com/faq/automatic-synchronization-is-not-run-as-expected/
Look at the Autostart section…
Does this solution work for you?
Only today I read this post and get a hint would could be a reason for many problems I have had with using davdroid with my Xiomi Mi Max 2 phone(android 7). I looked Android settings and learned that Davdroid was victim of fucking Xiomi battery saving/permission policy. After some setup my davdroid seems to syncing as excpected. I am developing own caldav server and this thing wasted several days of my time.
