Newsletter – Office 365 Headers Removal

Newsletter – Office 365 Headers Removal is a lightweight WordPress plugin designed specifically for those who send newsletters through Microsoft Office 365 SMTP servers. Its main function is to automatically remove the hidden technical headers that Office 365 adds to outgoing emails, which can cause messages to be blocked, marked as spam, or rejected by destination servers.

This add-on integrates natively with the popular Newsletter plugin and most SMTP plugins, so it requires no complex configuration: once activated, it processes each outgoing email and cleans unnecessary metadata before delivery. This significantly improves deliverability, antispam filter scores, and brand consistency, as recipients receive clean, professional messages with no traces of internal infrastructure.

Key benefits include the removal of Office 365-specific headers, compatibility with Microsoft 365, Exchange Online, and hybrid environments, support for transactional and marketing emails, and granular control to enable or disable header cleaning based on each site's needs. Additionally, it is compatible with WordPress multisite installations and offers hooks and filters for developers who wish to customize its behavior.

The plugin is designed for WordPress site administrators who use Office 365 as their email infrastructure and have experienced delivery issues, as well as for agencies and email marketing professionals looking to ensure their campaigns reach the inbox without interruptions. Its operation is safe: it only removes problematic headers and preserves all headers required by RFC standards, so the content, formatting, and workflow of newsletters remain intact.

With minimal weight and optimized performance, this add-on solves a specific technical problem without altering the rest of the email structure, making it an essential tool for any site that relies on Office 365 for its email communications.