Migrating old emails over to a new client might be non-trivial. My grandfather has many years of emails and attachments stored in Incredimail - some of whom have passed away, so he'd really like to keep these emails.
I've backed up his Incredimail email database, and will have to find a way to import them into Thunderbird or something similar.
Yup. Back when Incredimail was popular, IMAP was not as widespread.
I moved my mom over from Incredimail to Thunderbird 10 years ago, but I don't think I managed to import the message history... Now she's on gmail instead of the internet provider email (that has since been switched several times), so no longer an issue