Update on The Ultimate Challenge

We've got a quick update for you all on how the Ultimate Challenge (our 84 page book of puzzles) is proceeding: 

We can confirm that a number of people have made contact with us and appear to have successfully completed the Ultimate Challenge. Since we won't be making callbacks and eligibility checks until September 1st, we won't be able to announce the list of finalists until the first week in September.

Until then, if you haven't solved it yet, do keep at it! And if you're stuck, there are some fantastic player-created resources at the Crack the Code wiki (thanks to everyone there who contributed and set it up!).