Eos-updater no longer works

EOS Updater no longer works on the latest development branch (4.0.0~210321-230009)

eos-updater-ctl update dies:

Traceback (most recent call last):
  File "/usr/bin/eos-updater-ctl", line 422, in <module>
    main()
  File "/usr/bin/eos-updater-ctl", line 418, in main
    sys.exit(args.function(**args_dict))
  File "/usr/bin/eos-updater-ctl", line 217, in command_update
    poll_result = command_poll(block=True, quiet=quiet)
  File "/usr/bin/eos-updater-ctl", line 196, in command_poll
    return command_dbus('poll', block, quiet)
  File "/usr/bin/eos-updater-ctl", line 161, in command_dbus
    proxy = Gio.DBusProxy.new_sync(bus, 0, None,
gi.repository.GLib.Error: g-dbus-error-quark: Error calling StartServiceByName for com.endlessm.Updater: Failed to activate service 'com.endlessm.Updater': timed out (service_start_timeout=25000ms) (20)

The Log for the updater service shows:

‚óŹ eos-updater.service - Endless OS Updater
     Loaded: loaded (/lib/systemd/system/eos-updater.service; static)
     Active: failed (Result: exit-code) since Mon 2021-03-22 13:49:47 CET; 53s ago
       Docs: man:eos-updater(8)
    Process: 19059 ExecStart=/usr/libexec/eos-updater (code=exited, status=1/FAILURE)
   Main PID: 19059 (code=exited, status=1/FAILURE)
        CPU: 8ms

Mar 22 13:49:47 nevermind systemd[1]: Starting Endless OS Updater...
Mar 22 13:49:47 nevermind eos-updater[19059]: /usr/libexec/eos-updater: /lib/x86_64-linux-gnu/libostree-1.so.1: version `LIBOSTREE_2019.7' not found (required by /usr/libexec/eos-updater)
Mar 22 13:49:47 nevermind systemd[1]: eos-updater.service: Main process exited, code=exited, status=1/FAILURE
Mar 22 13:49:47 nevermind systemd[1]: eos-updater.service: Failed with result 'exit-code'.
Mar 22 13:49:47 nevermind systemd[1]: Failed to start Endless OS Updater.

This issue can be reproduced by installing a fresh 3.9.3 and then upgrading to the latest development branch.

Oops! yes, ostree got updated and we need to rebuild eos-updater because the symbol versions shifted around. Also flatpak and any other libostree users.