You can connect an I2C device to the board. The SDL and SCL pads are in the lower-center part of the board and are labeled.
You will have to do lots of coding to change the firmware to work with an I2C display. I suggest you create a new object like Display that controls the I2C device. I won’t be able to give you detailed help on this, as it would be a big project.
Thanks for your answers, Mike. But that is not what I need, I think I have expressed myself the same, probably because of the language, since I am Spanish and my English is not very good. What I need is to be able to connect another 7-segment LED display, the same as the one on the board but a little bigger. So I don’t know if I have to modify the Software. I put here a picture of the screen that I would like to put, if possible please.