Hello,
I have replicated your issue on the latest 07.04.3 FW and indeed, the SMS messages sent through Modbus Alarms did not include any diacritics. However, diacritics are properly included when using the regular SMS sending function.
I will communicate this issue to our R&D department and provide you with an update as soon as there is any information available.
In the meantime, have you experimented with other firmware versions? For example, version 07.02.7?
Kind Regards,
Andzej