I have an old 2004 Airport Express (802.11g I assume, not that the bastards ever label them clearly). I’ve been using it happily for remote sound for years, and was even happier when Apple finally made it possible for Airplay to work with apps other than iTunes in Mavericks (and now Yosemite) – so that at last I can watch video with hi-fi sound. (In VLC, go to Windows/Track Sychronisation, and set audio track sync at -2 seconds for perfectly sync’d sound).
Two days ago, I made the mistake of changing my wifi network password… and the Airport Express stopped talking to my network of course. Because Apple (why, oh why, oh why) has stopped supporting older APEs in Airport Utility, changing the settings on an Airport Express was a nightmare that started with trying to find ways of running old versions of the utility on Yosemite and ended with me dragging my ancient iBook (running Snow Leopard) out of a dark cupboard, downloading Airport Utility 5.6.1 – and then battling to reset the APE. Each time I did this (factory reset, holding in reset button, plugging in and waiting 10 seconds), the settings would take effect, but the new restored APE. would not then connect to my network.
To cut a long story short, I eventually sorted this out by changing the settings not on the APE, but on my router, where I switched the wifi settings to channel 1, 802.11g (it’s an old router), and WPA2-PSK encryption (previously I’d had WPA1+WPA2 selected).
Now everything is working perfectly again – my beloved Airport Express is de-bricked.