Since there was recently a long and contentious thread on exactly this topic, I feel like I should clarify.
Scrivener does not directly interact with any synchronization service on any platform, with the sole exception of Dropbox for iOS Scrivener. By that definition, we do not “support” any Mac or Windows synchronization service.
We do offer discussions of best practices and possible issues whenever we feel it’s appropriate. The relevant part of our Knowledge Base is here:
https://scrivener.tenderapp.com/help/kb/cloud-syncing
For any service, though, the vendor is the ultimate authority on what the service is and is not capable of. We are not Dropbox/One Drive/iCloud support.
We encourage users to do their own due diligence, recognizing that no one else will care about their data as much as they do. In particular, never rely on any synchronization service – including Dropbox – as your sole backup for critical data.