From the changelog:
Bug Fixes
Fix regression in 0.7.3 that broke creating custom columns of rating or text types
Fix cover browser breaking if you click on a book in the book list while cover browser is animated
Fix a bug that could be triggered with the new book details pane if a book has a zero size cover
SONY driver: Fix bug preventing the editing of collections in the device view
You’re missing a full stop between the 7 and 4.