Important update (as this has already caused confusion to some users):
The package Interact (on master branch) is now a metapackage based on WebIO, CSSUtil, Observables, InteractBase/Bulma/UIkit. See the documentation for details on how to use it. The most basic functionality (that is to say @manipulate) is preserved with the same syntax, whereas more sophisticated usage of the package may break. In particular, as the new framework uses Observables, rather than Reactive, one should call observe(widget) rather than signal(widget) to obtain an Observable whose value will update when the user interacts with the widget.
The documentation already reflects the new (as of now unreleased) version. If you are willing to try the new version already, you can Pkg.checkout("Interact") and experiment with it before it gets released, which could be helpful to catch bugs early on in the process / understand which features of Interact that were commonly used are not adequately implemented in the new framework. If on the other hand, you (or a package you are developing) rely on many features of “Interact” and want to make sure your code does not break, it is of course possible to do Pkg.pin("Interact", v"0.7.2") or add an upper bound to Interact in REQUIRE.