We should recommend using sparkle:version and sparkle:shortVersionString elements inside the appcast item instead of inside the enclosure for consistency.
Delta updates do not need to specify sparkle:version, and can inherit the top level element. This clears up some confusion and reduces duplication (and reduces error proneness / saves me work when testing delta / info-only features).
This is also consistent with informational updates. Regardless whether you want to make an update informational only or not, the sparkle:version stays in the same top-level place.
This is a backwards compatible change. Very old versions of Sparkle (possibly up to a decade or more ago) have supported specifying sparkle:version as a top level item. Winsparkle supports it as well because it's needed for info-only updates.
This is only changing what we recommend / standardize. The attribute variants are still usable.
External tools relying on Sparkle's feed format may have to adapt to this standardization (they have always needed to support info-only updates with a missing enclosure which apps do leverage anyway).
I updated generate_appcast to prefer the element variants and updated the tool so it understands them (this was a bug).
Zorg
Jordan Rose