I've been tinkering with this recently and there are conversations where the last content in the sqlite database is a month and a half old. Oddly in some cases there used to be newer content in there that had since disappeared.
If you are talking about data missing from the `text` column, for some reason it disappears after you read a message. The content is stored in a binary blob in a different column, which I parse like this: https://github.com/ReagentX/imessage-exporter/blob/c73bc4d66...
