Various devices are reaching the end of their promised support. See https://support.google.com/chrome/a/answer/6220366?hl=en
Cr-48 is already past its official EOL date, but we've continued pushing updates to those machines for the last several months.
We need a system for communicating clearly and proactively with users if their devices are going to stop receiving updates.
This issue tracks implementation of the communication mechanisms required to do that.
More info: goto/croseol and goto/croseol-ui (Google only)
Comment 1 by abodenha@chromium.org
, May 13 2016