They had self hosted sync with the old vault format. They removed it when they switched to the new vault format. Dropbox always worked. Now they push their own service.
No, it didn't. I don't remember the details, but the local sync (starting a sync server on the phone) did not work for me with a normal home network, and Dropbox didn't work across all devices, either.
No, it didn't. I don't remember the details, but the local sync (starting a sync server on the phone) did not work for me with a normal home network, and Dropbox didn't work across all devices, either.