Try the downloads section of DJI’s support page for the P3S. If you get the “For Your Attention” notice just close it. That support page has links to the apps (Apple and Android) as well as the latest FW and other docs such as the user manual, etc.
To be honest I thought Go app versions where the same for all that used them but just adjusted to what it was used with.
I must have been mistaken. What I posted is the current one I use with my Mavic .