iwmigrate Windows 6.7.2 to Linux 7.3.2

System

We are planning to move our current TS installation from Windows to Linux and from 6.7.2. to 7.3.2.
The Windows version is a current live installation, the Linux one is a new one in development by an external developer.
The goal is for both to run in parallel on the same Linux installation.

From what I have read on this forum can I assume that use of iwmigrate is out of the question?

Also does anyone have any experience or suggested timescales for such a move. (BTW I have been upgrading TS on Windows since TS 4; but this is my first cross-platfrom move )

Much thanks to all for any responses

/Nick