This app works well enough restoring the legacy UI. I finally gave up though for the following reasons;

The auto-update addon I also use stopped functioning after the last update. I assume due to some UI change.

The timeline would get crazy, many times showing things out of order, but this may be more of a twitter issue.

Unable to view timeline more than an hour backward.

If you simply want to use the legacy UI and don't care to see older timeline tweets, this is a good add-on.