Gmail is set to implement more strict bounce rules based on the RFC 5322 standard. The new rules will affect senders who are not transparent about their email authentication settings or who send messages with invalid or misleading information in the “From” field. These changes are aimed at reducing fraudulent and malicious email practices, such as phishing and spoofing attacks. If your emails are authentic and correctly formatted, you don’t have to worry about being affected by this change. However, if you’ve been taking shortcuts with your email security, you might want to review your practices before the new rules take effect. These efforts to improve email security enhance user trust and protection, making email a more reliable form of communication for everyone.
Excerpt from the main article:
A few days ago, Google started notifying (some) Google Workspace customers of updated spam filter/blocking changes coming to the Gmail email service. They’re moving to more proactively block emails that have headers violating RFC 5322, and it is believed that this is an attempt to help prevent DKIM replay attacks. Read on to learn more about what this means and how it could impact email senders.In the notification below, they indicate that they’ve sent this only to Workspace users they think may be impacted by this change, but truth be told, it affects the entire internet, as it could impact anyone sending email messages to any user at a Google-hosted mailbox.The notification: We’re writing to let you know about an upcoming change to your Gmail services. Gmail will start rejecting messages that are non-compliant with Internet Message Format standards and contain more than one single-instance email header as of April
Gmail: More RFC 5322 bounces coming– helping to impede DKIM replay attacks was originally published on Spam Resource: All Things Deliverability