Primary focus for this release:

Major

(Headline changes that would be sad to punt.)

• Integrate new theme engine (#848, #1600, #1263)
• Add Package/Grouped Product Type (#386)
• Make Store Reports and extensible API (#462)
• Recurring Sales API (#83)

Minor

(General improvements, completed iterations on prior enhancements, etc. Avoid punting if possible)

• Improved Stock Level handling (#720)
• Add an upgraded_from option (#1569)

Iterative

(Feature-as-plugins, minor enhancements. happy to punt.)

• Stats-API improvements (#739)
• REST API (#406)