Electronic
The watchdog IC U2 is not needed and should be removed from the PCB in the future. Same for snubber circuits C1 and R6 + C2 and R10.
The 230 VAC power supply Kamstrup supply does not give enough current for wireless peak usage, so we built our own with a 2A switched mode power supply from AliExpress supplier Kuuco's store customized to 3.6 V to keep the Kamstrup meter happy.
The Eagle PCB can be found in the GitHub project