General
Each announcement’s Enabled switch, which replaced the switch for all of them
Turning an announcement on or off
From 7.3.0 each announcement is turned on or off on its own, with its Enabled switch.
A new announcement is enabled. Disable in its row menu, or the Enabled switch on its page, hides it under the header and keeps it in the list, and Enable shows it again from its start date until its end date. The switch is saved at once.
The Show announcements switch of 7.2
Up to 7.2, a General tab had a Show announcements switch that turned all of them on or off at once.
From 7.3.0 that switch is gone. When it was off, the upgrade disables every announcement, so none starts to show: enable the ones you want again.