I think that something changed about the authentication scheme. It always says "device offline".
FWIW, if you fix this, would you be willing to consider packaging the systemd unit and the rules file separately? I've had much better luck with a more standard rules file setting mode 0660 and a sensible group.
I'am able to use adb with my Nexus 5(Android 4.4.2). For systemd usage there is a bug https://bugzilla.redhat.com/show_bug.cgi?id=967216 I'll fix it [van@vanzen ~]$ lsusb Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 003 Device 002: ID 18d1:4ee2 Google Inc. Nexus 4 (debug) Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 004: ID 064e:f300 Suyin Corp. UVC 0.3M Webcam Bus 001 Device 005: ID 13d3:3375 IMC Networks Atheros AR3012 Bluetooth 4.0 Adapter Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub [van@vanzen ~]$ adb devices * daemon not running. starting it now on port 5037 * * daemon started successfully * List of devices attached 03af1d62d0243fc5 device [van@vanzen ~]$ adb shell shell@hammerhead:/ $