This is the sixth alpha release. Major new features are postponed until Payment 7.x-2.x. Only bug fixes and small improvements will continue to be added to 7.x-1.x.
Until we are in beta, you will have to re-install Payment in order to update to a newer version.
This release fixes a critical bug that started presenting itself any time a new product line item type was created through the user interface. It's unknown if this bug was present in the 7.x-1.0-beta1 version or if it purely affected sites running 7.x-1.x-dev, but it was happening enough to warrant a new release.