I doubt that Smartermail will give you any support on Linux migration, so it all depends on how Smartermail stores e-mail data. If it is their own secret binary format, then it will be difficult. If it is some human-readable storage with easy to follow logic, then you can migrate with some custom shell script doing the conversion.
Other possibilities:
- see if Smartermail has some export function for e-mail data and test what you can do with it in terms of data conversion
- create a script (maybe PHP) to parse all mailboxes by IMAP protocol, retrieve all e-mail automatically and forward them to the new location (the new mailserver has to operate on a temporary IP location for this, or run the script from the computer that will become the new mail server)
KDE Programs Naming Convention