Hi
I was wondering if anyone knows if this product 7" Touchscreen https://www.sparkfun.com/products/13733 is compatible with rpi4 ? The catalog page says Pi 3 and nothing about Pi 4. meaning it could be old stock
-g
As far as we know, yes but we haven’t actually tried this combination. We have not had anyone mention to us these don’t work with the Pi4 so I think you’re probably OK. Just make sure you download the latest version of NOOBS since that will have all the necessary drivers for both the Pi4 and display.
The reason the display product page only mentions up to the Pi3 is that at the time the display came out, the Pi4 didn’t exist yet and it never got updated when the Pi4 came out.
At the moment, I’m logged into a MacBook Pro, and logging in with the RPi4 just to send the answer from it seemed a bit much hassle. 
Anyway, the answer is “yes it does work”. I also got a “SmartiPi Touch 2” case https://www.sparkfun.com/products/16302 for the display and RPi 4. It includes a cable that takes a USB C input (socket) and "Y"s it into a USB C output (plug) for the RPi 4, and a Micro USB output (plug) for the LCD display.