This is growing rapidly. I wouldn't be surprised to see it at over 6m in the coming few days, 10 million by the end of next week. Bare in mind it was 1.5m yesterday:
[PS4 Open Beta] As a THANK YOU to all 4.5 million+ of you who have joined us since Open Beta launch, we've dropped the Blue Barbed Hellfire 4-6 right into your inventory!— H1Z1 (@H1Z1) May 26, 2018
PLUS, Duos is now unlocked with a brand new patch - see the latest fixes here: https://t.co/ZC3AuC94uU pic.twitter.com/G3iLFmX1AZ
The PS5 Exists.