For Imager computers (subnet 54), if you don't want your machine to be upgraded, then turn off cfengine.
Frozen and non-frozen periods for updating machines will be determined at the Imager Tech Staff Meetings in accordance with the calendar of conferences. There will be a 48 hour notification on updates during the non-frozen period. No updates (including security updates) will occur during the frozen period. The updates will be tested on 'tom' first, and 'tom' will generate an email to imager-tech when it is upgraded.