There is no need to do adjust your email settings if you are an existing Vodafone Broadband customer. Your email will continue to work as normal when you upgrade to Vodafone Fibre Broadband.
However, if you are switching to Vodafone from another provider then you will need to change the outgoing mail server (SMTP) of your email client (Outlook, Thunderbird etc.).
The outgoing mail server (SMTP) for a Vodafone internet connection is: mail.vodafone.ie