The extras distribution now includes support for dynamic linking. The GNU Emacs interface provides a source-linked debugger. We've removed the support for using a Prolog debugger on Mercury programs. Mmake, the Mercury make tool, now includes better support for installing libraries. We've added support for user-guided type specialization.
Numerous bug fixes.
The Mercury type system now supports existentially quantified types. In combination with type classes, they allow you to write code in an OOP-like style. We now allow abstract instance declarations. You can declare in the interface of a module that a type is an instance of a particular type class, and provide the definition of that instance in the implementation section of that module. We now support a simple form of user-defined infix operators.