Scam Mail from Xmail or legit?

Good morning gareau2576! Thank you for sharing that you received an email like this as well. Thank you for being cautious and not clicking the link in the email. I have been fooled by things like this myself and I feel so silly about it after, but we all make mistakes. I've gotten better over the years to stop and check all my messages and even when I know it's a valid email, I still don't like to click a link. I rather visit the official site myself and perform what ever is needed. 

The main thing I check is who is sending the email. But if you are still hesitant please reach out. Specifically for our migration to yahoo with our comcast.net email address the sender would be xfinity@updates.xfinity.com along with our verified logo. However, even with the migration, if the account is eligible to transfer to yahoo, you can visit our official site xfinity.com, and you will be prompted there if you are eligible to migrate the account. 
The request for IMAP to update your password is specific to the email client on the device. The password is needed to allow the email client to access the comcast.net email server to retrieve your emails. You can search Xfinity email client settings to help guide you through making sure you have the email client set up correctly. I know I just talked about not trusting links, so you can easily search for that topic and the top results should show our support site for setting up email clients.