ACS OnDemand is a free, easy-to-use native app from ACS Technologies that gives you mobile access to your ACS OnDemand environment. Instant access to your ACS, PDS, or Headmaster software. Ability to print to a PDF Document. Run Checkpoint from an Android device. Requires Android 5. 0 (Lollipop) or later. Note: printing is not supported from the ACS OnDemand app.