I am having some wifi stability issues with a Particle Photon. I have had similar issues with an ESP8266 that was fixed by forcing 802.11b mode - apparently modern "smart routers" occasionally like to switch channels and some of these microcontrollers don't deal with that very well. This is evidenced by rebooting the router fixing the issue - when the device is having a wifi connectivity issue, rebooting the device or even attaching an antenna won't help, but rebooting the router will. It doesn't happen on all routers, but most modern expensive ones.
On an ESP board this is a very simple one line command:
Is there any such command for the Particle Photon to force it to 802.11b mode?
EDIT: I can confirm it is the router switching channels that breaks the wifi connection, because if I go into my router's page and manually switch, it also breaks the Photon. Interestingly only the Photons and ESP8266's that are near the edge of the wifi signal are affected, the ones inside with stronger signals do not need the fixing code and are able to seamlessly transition to the new wifi channel. I may just tell my router to stop messing with wifi channels to fix this in the meantime.