The members of the WebAssembly Community Group have reached a consensus that the initial API and binary format is complete. They announced this on the mailing list: https://lists.w3.org/Archives/Public/public-webassembly/2017Feb/0002.html

What this means is that developers can start shipping WebAssembly code, although it’s probably a good idea to also include an asm.js version for earlier browsers.

Exciting times!