Several images have been leaked for the upcoming Rock Event for Pokemon GO. The datamined images were taken from the current 0.63.1.
Charles, from the pogodev reverse engineering community, managed to obtain a preview of the upcoming Explorer (Adventurer’s) Hat and other images used for event, as they were downloaded once the 0.63.1 update was forced:
Now we don't want to hype you guys but based on the history of pokemon go updates, a force update always came before a big update. So, I think that the Rock Event will just be a few days away from its official release. In addition, we are also expecting the upcoming gym rework to hit right after the Rock Event.