To manage large email accounts on Xplornet without the need for additional server space for old emails (20GB+), you can set up a self-hosted IMAP archiving solution, like Dovecot, on your own server. This allows you to archive older emails locally while still using Xplornet's webmail system for sending and receiving messages. If multiple users need access, you can deploy a webmail solution like Roundcube or Rainloop. This setup enables you and your family to access archived emails and compose new ones using their SMTP credentials, similar to how Gmail or Outlook handle POP3 accounts. This way, you can maintain email accounts on Xplornet while archiving emails efficiently.