Disable SIS

Hi,

I'm currently running a small home-server with Dovecot. A long time ago I configured it with SIS enabled. I would like to stop using SIS.

If I remove sis from mail_attachment_fs will the old mails that are stored in SIS-storage still be accessible? How can I convert all mailboxes to stop using SIS and store attachments back in the mails?

Rgds, N.