Asics made more unexpected changes to their services on August 7th, which unfortunately broke the RunKeeper integration again.
This has been fixed already and version 2.54 is now awaiting Apple's approval for the App Store. This usually takes a day or two.
Thanks for your patience.
Fixed in version 2.54 released August 7th.
Thank you so much for being so brilliant about keeping up with RunKeeper’s frequent nonsense. It is frustrating but I know you guys always get in an update really quickly. You rock, and RunGap is my longtime favorite app. 😀