I believe the current goal is by the end of January (and the main blocker right now is v8 inspector support (debugging in Chrome devtools)).

However internally there are quite a few things need to refactor. Since Deno aims for better Web spec compliance, we need an overhaul of the Worker implementation we have right now. So likely existing API interfaces under the Deno namespace is stabilizing soon, but many of the Web-compat APIs still need frequent updates