this is the crypto stamp 2.0 ink:
https://imgur.com/TsP5k7tfound it in "Die Briefmarke 06/2020":
https://imgur.com/fYBPOFd page 28
also they got red ink so it is again special to all the other stamps but indifference to v1.0 crypto stamp 2.0 is no longer an official special stamp aka "Sondermarke" but a new kind of stamp (not sure if that is a good or a bad thing). There is a little article in German too but nothing new really.. can post it too if anyone wants.