Erik van Haren in de Telegraaf (Dutch newspaper): "It is game on around Max Verstappen, that much is clear. Within now and about a month and a half it will be clear whether the current number three in the World Championship standings will 'simply' continue to drive for Red Bull next year or will then switch to Mercedes.
Stories (read: rumours) about a deal between Verstappen and Mercedes are much too premature. That is not the case. Just like the multiple reports that the Dutchman can leave Red Bull for free, if that team is not in the top 3 among the constructors during the summer break. That too has been dismissed as nonsense by various parties involved for some time now."
"Verstappen indicated in May that the 'upcoming races' would be very important to him, also with regard to his future. Last weekend in Austria he said that he is still in that process. In summary: Verstappen wants to see that the considerably regressed Red Bull takes steps in the right direction and can make progress this month. Starting this weekend at Silverstone, where a new floor for the fickle RB21 will be introduced."
and more in Dutch here
https://archive.vn/MDPzD
So Erik van Haren indicates: Verstappen is seriously reconsidering his options which could mean that he will switch teams if Red Bull is not able to improve the car. So next weekend could be crucial since a new floor will be introduced (as stated by Van Haren).