I encountered problems on iOS after updating to iOS 10.x.x and logged the problem on github:
There is no solution as of this moment for soft-setup-js browserfied. The thing with that library is browserfy turns it into about 40,000 lines of code. I took the example of embedded softap setup (putting the web pages into the Particle device)
https://docs.particle.io/reference/firmware/photon/#complete-example
and rewrote it using jQuery (which most people are using anyway). So you can do the whole thing in about 250 lines of javascript (not counting the RSA library)