They can change how they license it from this moment on - but any copies they've already licensed continue to be licensed the way they were. So if they license

They can change how they license it from this moment on - but any copies they've already licensed continue to be licensed the way they were. So if they licensed it to you as GPL, and then say "From now on, shareware is the way forward!" then you can continue to share yours as GPL, fork it, etc.