So, I do not ask for more info on the chip (I can wait till October, or so)Nope, sorry, anything that's not on NXP's public website is covered by NDA. They will publish all the info (unlike certain Chinese chips...) but probably not until the chips are actually for regular sale.
I've read
https://blog.nxp.com/iot/i-mx-rt-series-the-crossover-between-applications-processors-mcus
http://www.nxp.com/docs/en/fact-sheet/I.MXRT1050FS.pdf
so I know the basic features, I'm interested in
but at which level of your priority list is a T4.0 prototype. I assume you will make a similar beta testing device as you did with T3.6.