This is the official Syllabus version since IOI 2020 (no major changes have been made since then). The Syllabus is an official document related to the IOI. For each IOI, an up-to-date version of the Syllabus is produced by the ISC, as described in the IOI Regulations, Statue 3.13.

        Syllabus (since IOI 2020)

The original proposal of the IOI Syllabus was co-authored by Tom Verhoeff, Gyula Horvath, Krzysztof Diks, and Gordon Cormack.
Since 2007, the following people have maintained the syllabus and made significant contributions: Michal Forisek, Jakub Lacki and Richard Peng.

The Syllabus is prepared and used by the International Scientific Committee of the IOI.
The most recent batch of revisions to the Syllabus was made by the ISC between February and July 2016.

You are welcome to send any feedback on the Syllabus to the current maintainer's e-mail address (forisek_at_dcs.fmph.uniba.sk).
For people interested in contributing to the quality of the Syllabus, some additional background on the Syllabus and other miscellaneous information can be found at http://ksp.sk/~misof/ioi-syllabus/

It might also be a good idea to look at problems from past Olympiads, which are available on the Editions page.