After some testing I can confirm that the %z bug was introduced in firmware 7.03 and fixed in firmware 7.04.
{"Hardware": "TRB245", "Firmware": "TRB2_R_00.07.02.1", "Timestamp": "1680202410", "DateTime": "30/03/2023 20:53:30", "MODBUS slave ID": 1,"Start register":400001, "data": [768,-30971,12580,1024,512,3612]}
{"Hardware": "TRB245", "Firmware": "TRB2_R_00.07.02.7", "Timestamp": "1680203609", "DateTime": "30/03/2023 21:13:29", "MODBUS slave ID": 1,"Start register":400001, "data": [768,-30971,12580,1024,512,3612]}
{"Hardware": "TRB245", "Firmware": "TRB2_R_00.07.03", "Timestamp": "1680259434", "DateTime": "31/03/2023 10:43:54", "MODBUS slave ID": 1,"Start register":400000, "data": [768,-30971,12580,1024,512,3612]}
{"Hardware": "TRB245", "Firmware": "TRB2_R_00.07.03.4", "Timestamp": "1680204134", "DateTime": "30/03/2023 21:22:14", "MODBUS slave ID": 1,"Start register":400000, "data": [768,-30971,12580,1024,512,3612]}
{"Hardware": "TRB245", "Firmware": "TRB2_R_00.07.04", "Timestamp": "1680204551", "DateTime": "30/03/2023 21:29:11", "MODBUS slave ID": 1,"Start register":400001, "data": [768,-30971,12580,1024,512,3612]}
{"Hardware": "TRB245", "Firmware": "TRB2_R_00.07.04.1", "Timestamp": "1680205034", "DateTime": "30/03/2023 21:37:14", "MODBUS slave ID": 1,"Start register":400001, "data": [768,-30971,12580,1024,512,3612]}
Can you update the firmware changelog so other users on firmware 7.03 - 7.03.4 who run into this problem will know they have to upgrade?
For example add %z to the "Fixed Data To Server JSON format %n, %N and %s flag issues" line.