AC Central v.4 is currently in beta testing and it includes a filter by hymnbook feature. And the new search function lets you search within a specific hymn book.

Any missing hymns from any of the books currently included in AC Central are because of copyright limitations. The same is currently true for Hymns of Worship, but we are really close to getting agreements with most of those publishers (they have been very slow in responding to our requests) and expect to have those songs added in the relatively near future.

This is good feedback. We will check with the developers to see what it will take to fix that.

That is because this song (and numerous others) is copyrighted and we do not currently have permission from the publisher to post this in a digital format. That might change in the future if we can reach a reasonable agreement with publishers.

That's correct. That is one of the few songs in the Zion's Harp which is under copyright and we currently do not have permission to post it. 

We are currently testing the v.4 mobile apps. You'll know when it is released because it looks completely different. The browser versions have not yet begun extensive testing so smart TV browser compatibility is not yet determined.

Dark Mode is on our list of features to add in 2023, budget permitting.

Thanks for letting us know. This has been fixed.

Thanks for reporting that. It has been fixed. You will need to delete the song and re-download it to see the correction.