Run it in the background
Without this, you only receive while something is running. The daemon keeps your inbox and the local-network receiver alive with no terminal and no app open, shows desktop notifications, and refreshes the trusted-device list on a schedule.
It is off by default.
s2u daemon install # enable it for your users2u daemon statuss2u daemon logss2u daemon stops2u daemon uninstalls2u daemon run # run in the foreground instead, to watch it workOn Linux it installs as a user service, so it needs no root and stops when you log out unless you have lingering enabled.
The daemon never trusts a device on its own and declines unknown senders, exactly as the CLI does when you are sitting in front of it. Running unattended does not widen what is allowed.