Apple's full release notes for iTunes 12.7.4 are below:
iTunes now includes a new music video experience for Apple Music. Find what's new and popular in Music Videos within Browse, and play videos back-to-back with music video playlists.Today's iTunes update can be downloaded from the Mac App Store for free using the Software Update function.
iTunes 12.7.4 follows iTunes 12.7.3, a January update that introduced support for HomePod. iTunes 12.7, released last September, was the last major update to iTunes, eliminating the built-in App Store to focus solely on music, movies, TV shows, podcasts, and audiobooks.