26.3.7. Version comments
Any data version can have a comment that allows you to comment on the version in some way. To edit a comment, use the WriteComment() method. The maximum comment size is 1024 characters.
The system also provides the ability to specify a comment directly during the recording of the data object. For it, use the WriteDataHistory.VersionComment property upon writing versioned objects. The comment will be formed for the version which will be created in the result of the current object writing.