No specific info about version 4.0. Please visit the main page of OmniOutliner on Mac Informer.
A useful utility, might be not the best one, but it is pretty interesting for sure.
Scribe is the most intuitive outliner on the Mac.
Recovers a wide range of data from iOS devices and backups.
Put everything in one place, take notes and brainstorm.
OmniWeb is a powerful, feature-rich alternative to the standard web browser.
A tool to build Helpbook files from OmniOutliner documents.
A useful utility, might be not the best one, but it is pretty interesting for sure.