I have my domains at name.com where they are pointing to cloudflare DNS name servers.
After changing webhost I have changed my server IP address at CloudFlare.
My setup is this:
A localhost points to 127.0.0.1 Automatic A example.com points to xxx.xxx.xxx.xxx Automatic CNAME direct is an alias of example.com Automatic CNAME ftp is an alias of example.com Automatic CNAME mail is an alias of example.com Automatic CNAME www is an alias of example.com Automatic MX example.com mail handled by example.com Automatic
However - after 48 hours - I am receiving email on both my new and on my old webhost email (i.e. I have setup two email accounts in thunderbird - both email@example.com - that each check a pop3 at either the old or new webhost)