IP will change more often
The Magereport servers are now running on a new cloud system, that treats the servers like cattle rather than pets.
Long story short the outgoing IP of Magereport will change more often.
Keep an eye on magereport.com/static/ips.txt for the current outgoing IP. If you want to automate the whitelisting of the outgoing Magereport IPs, you can use: magereport.com/static/ips.json.