I have a collection of Macs from the 2000s, including the iBook G4 and the iMac G4. The iBook G4 still connects to wi-fi, and I've seen this update prompt on my iMac G4 (which is connected to Wi-Fi using a mini wireless access point).

I use my iMac G4 to play songs on iTunes, I keep my music library on a server with Samba installed and I mount the volume with the files. I love the Cover Flow design from older iTunes. I can also push songs to my iPod this way.