In my environment to use Resilio Sync, its fundamental to sync with my NAS MYCLOUD MIRROR (not GEN2). I first tried to install the GEN2 binary there, but it rejected with an error. After a while waiting for a response by Sync Support and not giving up I tried to load the other WDMycloud binaries. And really, the last one for EX2 does it:
https://download-cdn.getsync.mcom/2.5.7/WD/WDMyCloudEX2_ResilioSync_2.5.7.bin
Now I'm happy to found Resilio Sync because it makes possible what WDsmartdrive doesn't, which I deeply disappointed uninstalled before.
Whith the default settings it seemed, the Mirror frequently hangs in indexing. As the hints in the web to disable the indexing processes didn't help, I modified some settings underAdmin-menue\settings\Network as shown in attachments and so optimising the NAS for networking with Windows. Maybe it was helpfull to regenerate the index database under ..\common\cloudaccess too.
Now the Mirror has constantly performance enough and is a real home cloud. I finally can use it to sync my PC with a tablett, backup picture from a smartphone and so on.