[Andrew]

OmniOutliner 3 used system-provided date formatting support that was different from ISO-standard date format, and could not represent a number of desirable formats. Since v3's release, the system date formatting support changed to the ISO standard, and we adopted that for OmniOutliner on the iPad and for OmniOutliner 4. While in many cases we could do direct translations, in some cases we couldn't, so a given format may be different between version 3 and version 4. If a date format set in one version gets read in and then re-saved with the other version, the format can change. (Especially when saving on OmniOutliner 3, which simply doesn't have any knowledge of the newer formatting.)