This product is not compatible with Raspberry Pi 4.
GrovePi+ are compatible with Pi 2, please check the details from Dexter's blog.
What is GrovePi+
GrovePi+ is add-on board with 15 Grove 4-pin interfaces that brings Grove sensors to the Raspberry Pi. It is the newest version compatible with Raspberry Pi model B/B+/A+/2/3 perfectly.
GrovePi+ is an easy-to-use and modular system for hardware hacking with the Raspberry Pi, no need for soldering or breadboards: plug in your Grove sensors and start programming directly. Grove is an easy to use collection of more than 100 inexpensive plug-and-play modules that sense and control the physical world. By connecting Grove Sensors to Raspberry Pi, it empowers your Pi in the physical world. With hundreds of sensors to choose from Grove families, the possibilities for interaction are endless.
NOTE: The Raspberry Pi board is not included.
What is New
Compatible with Raspberry Pi model B/B+/A+/2/3 perfectly
Faster SPI and higher reliability UART connections
Easier to assemble camera cables and LCD cables
Simplified procedures of firmware update
How to use
Step 1 - Slip the GrovePi+ board over your Raspberry Pi
Step 2 - Connect the Grove modules to the GrovePi+ board