Yep, the earlier caps kept failing due to the ethanol warping them and making them leak. My 2010 600 had an earlier version cap and it was a PITA to get back on correctly. The dealer swapped it out for free as per the notice from Stihl, and the new one worked fine. My FS90 has the newer style flip top cap, and it works great as well. I like the last version they came out with better than all their other caps, but too many people had complained and they went back to screw on caps, though they make several versions of it now.