02/14/2011 is the latest update that I see. Don't know 'bout bugs but have noticed that some of my calculations, in an attempt to figure estimated dynamic spine seem to give numbers that don't match with how the arrows are flying. To rephrase, I plug in my numbers and it appears that my arrow is underspined compared to the "required by the bow" number. I purchased wood shafts that ended up being about 10 lbs. over what ended up working better with my bow. When I punched in numbers for MFX carbons, I got the same result: Based on Stu's calculator, the carbons I ended up purchasing should have been right but turned out to be overspined. Not saying this is a bug, just talking about what I have experienced. It IS nice to have a tool for calculating total arrow weights and other estimates but spine calculation wasn't accurate for me shooting my bow.