purplegreen MDM is being prepared for its first pilot. These pages describe the development release.

What "offline" means

Google's Android Management API has no heartbeat. A tablet reports to Google when something changes and otherwise roughly once a day. "Last seen" is therefore the most recent of two times Google gives us: the last status report and the last policy sync.

• A tablet counts as offline when it has not been seen for longer than the tenant's threshold, 26 hours by default (adjustable in the tenant settings).
• So "offline" is measured in hours, not minutes: a tablet that was unplugged an hour ago can still show "last seen 3 hours ago" and not be flagged.
• If your kiosk app already talks to your own server, it can send a heartbeat to purplegreen-mdm (Heartbeat ingest: minute-level offline detection). The device page then also shows "App last seen", which is minute-accurate, and the Offline rule can use it.
• A tablet offline for 270 days must be set up again from scratch; the dashboard warns from day 240.