I’m using a Synology NAS DS220+ running DSM 6.2.4-25556 Update 3.
I recently updated ZeroTier by uninstalling the previous version from the Package Center and manually installing version 1.8.6, again from the Package Center (no Docker install).
From the Package Center I can see that ZeroTier is “Running” but I cannot find ZeroTier One in the Main Menu to change the settings. I also tried running sudo zerotier-cli status via SSH and I got -sh: zerotier-one: command not found.
I can confirm that following this thread I managed to get ZT 1.8.7 to work on my Synology running DSM 6.2.4-25556 Update 5. Thanks @dbronson for bringing this to my attention and of course thank you @zt-joseph for everything.