It looks like lbicelyne's still preparing to integrate WiFi into the emulator's next release, as it's again the centerpiece of this demo release. I couldn't find any mention of whatever bugs this release fixes, apart from the following instructions on getting it to work:
1. Switch on wifi, All PSPs choose p2p in Wifi Game menu. You should also change your controller as well. P2P mode could work and all psps have display.
2. Every PSP choose the same game. If you are using p2p mode, please use sync game menu on the 2nd PSP. You can press left/right to select sync game menu on reset game menu.