Dru 1.7, a major update, is currently in beta and will hopfuly be arriving in the Mac App Store during the summer. This will be a free update to Dru 1.6.3.
Major updates for Dru normally jumps two point in revision numbers (for example: 1.4 to 1.6) but time will only jump one point (1.6 to 1.7). Dru 1.7 will be the first of 3 major updates planned for Dru over the next 12 months.
The 1.7 update will have Enhanced Retina Support for those cool Macs with Retina displays. And other cool updates. Stay tune!
More details to follow.
Disclaimer: Specifications may change without notice.