How can teams stay informed of updates during the contest?

This website is the single source of truth. An atom feed is available to monitor.

How can teams contact the organisers?

Teams can ask questions in the #helpdesk channel in our Discord Server or tweet to @icfpcontest2021.

If you would like to contact us privately, you can email me and m at the domains alang.ca and jaspervdj.be, respectively.

Is it allowed to use commercial libraries, compilers, etc.?

Yes, if you have a license to use that software. Please note that you need to submit your source code for the contest to qualify for prizes. This includes the code that uses the commercial software, but not the commercial software itself.

Can poses submitted before bonuses were introduced unlock bonuses?

No, even if these poses placed a vertex at the bonus location, they will need to be resubmitted to claim the bonus.

Can a problem unlock a bonus for this exact same problem?

No, the bonuses available in a problem are always for other problems.