Sorry for all the confusion with the beta 3 expiration warning. Beta 4 is now available for download. Nothing major in this release as we're approaching the final version. We did fix a crash that would occur when saving under certain conditions. Unfortunately there is still a crash that can happen when you expand a PDF attachment after saving. This crash is very finicky so we've haven't been able to track down the exact cause yet. We also fixed a couple bugs that were introduced in the last beta.
Please see the release notes for full details. Head on over to the download page when you're ready, or use the built-in updater if you're using beta 3 (OmniOutliner menu -> Check for Updates). If you have any feedback on this release, please let us know by using the Send Feedback option under the help menu or send an email to email@example.com. Thanks!