This was rolled out yesterday. And no you don’t need to change your config. Your extensions can be any technology dahdi, iax, chan_sip or chan_pjsip. But to use Zulu you must at least enabled pjsip (Hence me stating “You can’t use it with chan_sip only”. There is no way around this. Zulu requires chan_pjsip. but that doesnt mean your extensions have to be chan_pjsip. Never said that.
If your extension is chan_sip and you use zulu then zulu creates an ad-hoc device in the background for the chan_sip extension in pjsip. Again you have to enable pjsip though for Zulu to work and be able to do this.
WebRTC does the same thing.
This was done because chan_sip is no longer supported by Digium. It’s a deprecated channel driver. New features for WebRTC are being added to pjsip, not featurss and bugs and security issues are also not fixed in chan_sip.