Users tend to not understand technical details - they often think: “I’m getting ripped off here - so they only added a multiplayer mode and I need to buy a whole new version” or “I’m getting ripped off here - they didn’t put a multiplayer in the first version so that I need to buy their game again a second time”.
I know, it’s not rational, but that’s how non-knowing people are. So you better tell them “I’m just a single indie person who made version 1.0” and “It’s very hard to write a multiplayer networked game compared to writing a single player non-networked game.” (you know it - but they don’t) Maybe users will understand it then…