A user recently had the desire to move away from the email client they’d been using for some time, and had requested assistance. In this case, they were using a version of Pegasus (Version 4.6, I think). Vaguely recalling that you can import data from various email clients to Thunderbird, I looked for a tool to convert the folders in the /Mail/ directory for Pegasus to something Thunderbird would use. Having read a little about it, I knew I needed to find a way to convert the folders to .mbx files, and found one called Mail System Converter here. It was then possible to move the folders and retain the email in a new client, or move it to an account on a server.
First install Thunderbird, and then add an IMAP account using your credentials. Having made sure this is connecting correctly, close down Thunderbird.
Using Mail System Convertor, you can use the ‘Folders’ menu, then select ‘Export from Pegasus’ to create files usable by Eudora. Having done so, simply move these .mbx files to:
Open Thunderbird again, and you can now see these as local folders. If you so wish, you can now drag them to your email account on your server.