More reliable migration from old Sparkle versions
No changes since 1.12 apart from change of framework's bundle ID from org.andymatuschak.Sparkle to org.sparkle-project.Sparkle.
This helps updating apps containing older versions of Sparkle (1.10 or older) which looked up resources by bundle ID and could get confused if another copy of Sparkle was present. Sparkle 1.11 and later is immune to this problem.
OS X 10.7 or later required
Make sure you add <sparkle:minimumSystemVersion>10.7</sparkle:minimumSystemVersion> tag to <item>s in your appcast. Sparkle will crash on Snow Leopard.
HTTPS or ATS exception required
OS X 10.11 deprecated HTTP and blocks updates unless you use HTTPS or disable App Transport Security.