Do I need Premium to app stream on local-only network?

[mostly]

I'm setting up a simple NAS at home (hard drive connected to router), and was thinking of running a media server on a raspberry pi. I'm still shopping around for media server software, and I'm hoping someone can clarify Subsonic's Premium app streaming feature. So, I'd need Premium in order to connect to my subsonic server through a native mobile app (right?). Now, what if I don't care about making my server accessible outside of my home network - could I access it through an app while on the same network without premium?

Basically, I want to be able to control my music from either my computer or phone (and output it to Chromecast). I'm not opposed to paying for premium, but it's just not clear to me if I'll need it given that I just want a locally-accessible server. Does subsonic even have a local-only option?

Thanks for your time! I've used subsonic a bunch through work (just as a user) and really like it.

[mitrailer]

Hi.

You can use the subsonic web interface locally for free... forever , but to connect to a mobile app you need the premium version, no matter if its locally or not

Cheers

[mostly]

Thanks!