GMT 4.x continues to see both development of new features as well as corrections of legacy bugs and problems. It is likely we will continue to do so for a while until we reach a stable point from which we can initiate the GMT 5 development branch. GMT 5 will be distinguished by being completely restructured so as to allow developers to call high-level GMT processes from a variety of programming environments. Below is a brief history of the development milestones in the 4.x series.