Just in time for (aka, National Novel Writing Month), Nisus Software has released  with some fixes for problems that crop up in macOS 10.12 Sierra. In particular, the powerful word processor addresses a crash that occurred when using the document version browser (File > Revert To > Browse All Versions); fixes incorrect spacing, indentation, and drawing that cropped up with the use of Soft Return characters; and eliminates a warning about invalid bookmark data that appeared after relaunching. The update also fixes a problem with using the system’s Markup feature on an image and restores LinkBack functionality for OmniGraffle.
If you purchased Nisus Writer from Nisus Software, you must the update directly from the Nisus Web site as the automatic update in the app is not working. Note too that  has been updated to version 3.5.6 with the same changes. ($79 new from Nisus Software and the , free update, 225 MB, , 10.8.5+)