Maybe I'm a bit weird, but I would never commit to using something if the person making it wasn't providing a consistent interface. It could well be different in your case, but as a general rule, a sub 1.0 version is software that isn't yet ready to be used. The vast vast majority of projects that say "you can use this, but we won't provide a consistent interface yet" end up either dying before they get to v1 or causing so much pain they weren't worth using. I can see this issue being especially bad in Rust, where small API changes can create big issues with lifetimes and such.