Hi Erik,
2015 was a Smalltalk-sabbatical year for me Erik, that's one of the reasons why as you see in the github commits, development has not moved further. But to be honest there is more, the direction of Amber doesn't look too exciting to me because in the end, the frontend productivity output is not convincing me anymore.
In the frontend/Smalltalk world this is way more interesting than Amber:
https://bertfreudenberg.github.io/SqueakJS/But I after the initial modest interest on flow-stack, the reality check of the lack of strong commercial projects on it made it stall. Maintaining a framework is not a small thing. Not being backed is a no-no.
But it's all MIT so anyone can take over and give it life on its own if found valuable.
BTW I'm currently quite happy with Meteor myself.
Feel free to ask anything