Destroying GPRS 1.X Shield by turning on I2C on Arduino?

Hello Guys,

i have an older GPRS Shield bought from a Friend and it is manufactured by you.

Now I have seen that the I2C Pins from the Sim900 Chip are routed to the Arduino Header. The Sim900 Pins aren’t 5V tollerant, so it can be dangerous to switch the Arduino I2C on? I2C on Arduino doesn’t operate at 2.8V.

Must I cut the connection to the Sim900 Pins? I dont want to destroy the Chip, there is no levelshifter. And also the I2C doesnt work without the special Firmware. So why are these Pins routed?

Miss I something and the Sim900 Chip is save even without cutting the connections?