Here are the final pre-production prototypes, and plots showing uncalibrated and calibrated S21 floor. PCB files will be released when V2 is available for order. The LCD connector can accept the 4 inch ST7796S LCD as well, and firmware support for that will be done before product release.
Note that not all of the shield can positions will be populated in production: some shields positions are found to give no performance improvement. The characterization of S21 floor was done with only 4 shields populated. If you get a unit with only 2 to 4 shields populated it's not necessarily a fake!