Announcements

An announcement is a message the jury publishes to everyone taking part in a contest, while it runs — a correction to a statement, an extension, an instruction about the room. Participants see it in the contest interface and cannot reply to it.

Announcements are on the contest's Announcements tab. Reading them needs permission to read contests; writing them needs permission to write contests.

Publish an announcement

Open the contest and go to Announcements.
Click New announcement.
Write the subject — up to 255 characters. It is what participants see first, so put the problem letter in it when the message is about one problem.
Write the message. The editor takes headings, lists, links, images, code, tables and mathematics.
Publish.

It takes effect immediately. There is no draft and no scheduled publication, and the announcement starts out unread for every participant, badged in their contest interface until they open it.

Mathematics is the reason the message editor is a rich one: a clarification about a bound needs the bound in it, written properly. See LaTeX for the notation.

Correct an announcement

Edit rewrites a published announcement in place. It keeps its identifier and its original time, so it stays where participants have already seen it rather than jumping to the top of their list.

Correcting is better than deleting and republishing: participants who read the original will not be told to look again, and a contest that publishes the same clarification twice reads as a contest that does not know what it is doing.

Delete an announcement

Delete withdraws it from every participant, including those who have already read it. There is no restore, and no notice that anything was withdrawn — which is why it is the wrong tool for a message that was merely wrong.

What announcements are not

A conversation. Participants cannot reply. A question raised by one participant is a ticket, answered privately — see Questions from participants.
A read receipt. Read state is kept per participant and drives the unread badge in their interface, but the console does not report who has read what.
A place for the rules. Anything that has to be readable before the contest starts, or after it ends, belongs on a contest page. Announcements exist for what could not be known in advance.