Hi, GrahamN.
I agree that the Drobo Apps behavior regarding the Drobo NAS version of Resilio Sync is very annoying, and I assume that you are referring to the notifications that appear in the right lower corner of the screen in Windows 10. These really should not be present for a version that is higher than the Drobo App Store version, but I have discussed this with Drobo support, and either they don't get it, or they don't care. Not only that, but they also will not acknowledge or fix the settings icon being grayed out, which prevents launching the Sync web interface for your Drobo. That can be easily worked around by using the following web address:
Drobo_IP_Address:8888/gui/
I might text the CEO someday, because he seems to get a lot. I just gave up and now, I just go with the Drobo Apps Server updates and accept whatever their latest certified version is. They will always be well behind, just accept that as a fact.
Anyway, that issue we can't fix, but if you decide to update manually to the latest version of Resilio Sync for Drobo NAS, you can suppress the erronious "version update" notification that displays by right-clicking on the Drobo Dashboard Icon that shows in the right side of the Task Bar, and then clicking "Hide Alerts"... any way, see if that helps.