Google I/O is one of Google’s biggest events, meant to show off the biggest new additions coming to Google’s many different products.

The focus has always been on developers, though, and namely Android, which makes it one of the key focal points for Google to unveil the next iteration of the popular operating system. Earlier today, the official Android Developers Twitter account teased a puzzle that, if decoded, would reveal something exciting.

That exciting thing, as discovered by a group of developers, is the big date for I/O this year. According to the puzzle, Google I/O will take place between May 17 and May 19 this year. It will be held at the Shoreline Amphitheater in Mountain View, California.

Of course, what Google plans on unveiling there still remains unknown. But at least we have a date to circle on the calendar.