The aim for 1.0 is for the end of this year; it will offer backwards compatibility at the language level (syntax and semantics of language constructs), and a subset of the standard library. The rest of the library will stabilised progressively.

(The compiler warns/errors when using a nonstable language or library feature, so it will be easy to stick to the stable parts, or at least know what may need to be adjusted when updating. The goal is to a strict semantic versioning plan too.)