for low amp boards, 3mm holes to hold the MOSFETs in place has been added
at the DIP switch, holes have been added (for ease of adding external (miniature relay) control of a channel)
using 0805 size components (are easier to hand solder)
because gerber import (to a different design software) was not complete/correct, all copper paths were re-designed (like: GND copper paths are now all connected)
added IDC 10-pin option (for easy connect/disconnect of RasPi control pins)
added extra pin rows so the dual rows of the “Wemos S2 mini” (ESP32 27-pin) controller connects to the board
8 of the extra S2 pins are available as an 8-pin IO connector
added an option to use a switch-mode '12V → 5V DC-DC converter' (max 90V or max 28V options)
added a 5V pin-connector at the bottom edge of the board
added a GND screw-terminal/connector at the bottom edge of the board
added solder stripes to the bottom layer - so additional copper strips can be soldered to the board (2x 64amp strips can be added)
additional power-in connectors/options (blade connectors and/or screw-held ring-eye-lets
option to use screw-held ring-eye-lets as power-out connectors
added a DHT22 connection header (S2 mini option on pin D21)
option for external 12V power-in going to 12V → 5V converter - so a simple on/off signal can remove power from the MCU (and thus can turn the entire board OFF) - in low-battery-voltage situations
option to dedicate one of the MOSFETs to control the 12V power going to the C3 boards - so a simple on/off signal can remove power from all the MCUs on all the C3 boards (and thus can turn OFF all the C3 boards) - in low-battery-voltage situations
added a 100nF capacitor to the A0 analog input (might help stabilize the analog reading a little bit)