Thanks Abhilash for your quick response
You can just take a database dump and migrate that. If you are using postgres, there is a pg_dump command that I know of. I am sure something exists for Mysql/mariadb too. I would recommend using this method for migrations.
You can also use django's dumpdata1 and loaddata commands to export and
import data from one installation to other. It should work when moving from one database type to other in theory. I haven't tested it to comment on how successful it would be.
Using pg_dump would work when migrating all lists from one server to another, but can't be used for migration of a single list. However, I guess it would be possible to write SQL script for that.
It turns out HK strips the angle brackets
< >when internally storing the message-id and in-reply-to header. It adds them back to Message-ID when exporting but doesn't add it back to In-Reply-To. I have opened 1 for the issue.Because of that, when the header is folded, an additional whitespace is added to the start resulting in broken threads.
Thanks for confirming this issue.
Regards, Goran T