~ All the slots are with 96% RTP and they don't change with the promos or with the casinos .. so forever 96% 
~ and the RTP is always de same 96%, never change 
Thanks for your replies, @ENDORPHINA, but how would you comment on these words on bitcoincasinokings site about Windy City slot by Endorphina?
"There is also a Double Up feature, where you can double your winnings. The Return to player rate is only 84 % in this feature, so ..."
Is it true? And if yes, are there any other features on Endorphina slots with which we can get a different RTP than 96%?
Its true we have a Double Up feature, where you can double your winnings but the RTP is always 96% never change, actually, here the player has the option to see the card of the dealer first
so you can call or not. regarding the website, they don't have the new releases for 2022 but I will try to contact them