R1
Initial Version - 1 prototype manufactured at Ragworm
R2
Invert signal coming out of first 74HCT138 - no boards made
R3
Increase resistor pin spacing slightly - 20 boards manufactured at Elecrow
R5
Change silscreen text, increase pad size from improved solderability

2020-06-19 Existing r5 released under CERN OHL-P v2 with no other changes