There are several new premises:
forall/require: tests, or gathers, all solutions to a set of goals (such as all elements of a tuple).
notany: verifies that no solution exists for a set of goals.
python: allows adding arbitrary python statements, which can set python variables.
first: only produces the first solution for a set of goals, then fails on backtracking to prevent other solutions from being considered.
The sqlgen and web_framework examples have been updated to use these new premises and many comments added to their .krb files so that they are easier to follow.
The web_framework example now caches its plans. This shows an example of caching and reusing plans and should make this example the fastest python web framework out there!
Read the release notes for the complete list of enhancements.