L96NR01A02S I2C problem

I purchased a L96NR01A02S Module (v2.1) for prototyping as the datasheet said that UART and I2C could be used with it. UART is working fine.
But as I tried to interface with I2C nothing worked. To my surprise my measurements yielded that the same data that was present on the UART TX was also sent on the I2C_SDA Pin but as a UART Baudrate 9600 Signal. I first thought that the chip was somehow configured to have 2 UARTs but the pin I2C_SCL does not seem to receive UART packets.

I found that the Hardware Design v1.3 Datasheet says: “I2C interface is supported only on firmware versions ended with SC.”
How can I know which firmware I have? PMTK Query results in “$PMTK705,AXN_5.10_3333_17102400,0008,Quectel-L96,1.0*35”

Or how do I get I2C working at all?

Thanks for your suggestions!
Greetings Thomas