Enviro+ and gpio #4

Good afternoon.

I use the Enviro+ with the PMS5003.

On the hat, gpio pin #4 is accessible.
Is it free for me to use freely, or is it connected internally or to the PMS5003 ?

Thanks for advising.

Guibert

All the pins broken out on top are for you to use however you see fit.

Thanks for the quick response !

Keep safe !

Guibert

Enviro Plus at Raspberry Pi GPIO Pinout

Looks unused to me. =)
It is used by some of the Pimoroni Breakout Garden Breakouts that are setup to use i2c. That would be my guess as to why it was brought out with the i2c pins etc. Those breakouts use pins 1,3,5,7,9 which are 3.3v, SDA, SCL, GPIO 4, and Ground.