In Version 2108 of Office 365, the character limit of msoPropertyTypeString seems to have increased beyond 255. I’ve stored a string over 500,000 characters long. Trying to find out if this will continue to be supported in future versions.
This fails in Version 2102, which truncates the string to 255 characters.
I haven’t found a place in Excel to store/persist a very long string (>100,000) so it was very convenient to use the CustomDocumentProperties. Hoping someone knows if this is official/permanent.
A good implementation: http://www.cpearson.com/excel/docprop.aspx
Microsoft’s documentation is lacking: https://learn.microsoft.com/en-us/office/vba/api/office.documentproperties.add