Ahum,
it was pointed out to me that I must be using some kind of obscure calendaring system since the Gregorian calendar which is most widely used nowadays has Aug 26 being a Tuesday. Now I could argue that the given date is correct and that the Monday is actually based on the western hemisphere whereas the Aug 26 date is based on the Eastern hemisphere. Factually correct but it doesn't make much sense (true, I have been accused of that myself more than once). More so because I had also stated the time of 23:00 GMT.
So to make it clear for everyone, the deadline will be
Tuesday, Aug 26 at 23:00 GMT. Gregorian calendar. And all hemispheres. On Earth at least. For other celestial bodies please consult your local stargazer.
Frank