Maybe it is just magic but it looks like to work so far.
Just try by yourself to find corner cases.
I will add comments here if/when I find issues with this configuration.
Hello i try to implement the discovery with one of them, but didn’t get none working.
and i added a SRV record for _caldavs._tcp if i try it with http://mxtoolbox.com/SRVLookup.aspx i get the correct entry, but in dravdroid i only see “Didn’t find caldav service”
thanx in advance
Please have a look at the verbose logs of the detection process. You can find every single step, including SRV and well-known resolution, in those logs. For more information about SRV records and well-known URLs, see https://davdroid.bitfire.at/configuration/#c64