Summary
When facing spam filter issues with older Outlook versions, a multi-faceted approach is recommended. Start by assessing the relevance of older Outlook clients in your audience; if they represent a small segment, optimization may not be worthwhile. Since testing tools may be unreliable, test directly in Outlook. Optimize for Outlook's Word-based rendering engine by using inline CSS and avoiding complex CSS or JavaScript. Email authentication (SPF, DKIM, DMARC) is vital, but a holistic approach including content and list hygiene is necessary as older clients may not fully support modern protocols. Avoid spam trigger words, optimize images, and maintain a clean email list. Check your IP against blocklists. Utilize email testing tools to identify Outlook-specific issues and adhere to SMTP standards.
Key findings
- Audience Relevance: Assess the significance of older Outlook clients in your target audience.
- Rendering Engine: Older Outlook versions use the Word rendering engine, limiting CSS support.
- Email Authentication: SPF, DKIM, and DMARC are crucial for improving deliverability, but older clients may not support them.
- Content Optimization: Avoid spam trigger words and optimize images for improved filtering.
- List Hygiene: Maintaining a clean email list is essential for sender reputation.
- Testing: Test emails directly in Outlook to assess rendering and filtering issues.
- Blocklist Status: Check if your IP address is on any email blocklists.
Key considerations
- Optimization Effort: Determine whether the effort to optimize for older Outlook versions is justified.
- CSS Compatibility: Use inline CSS and avoid complex styles for compatibility with the Word rendering engine.
- Protocol Support: Recognize that older clients might not fully support modern email authentication protocols.
- Content Scrutiny: Carefully review email content to eliminate potential spam triggers.
- Sender Reputation: Proactively manage sender reputation to avoid blocklisting.
- Testing Strategy: Implement a robust testing strategy that includes sending directly to Outlook inboxes.
- Standards Compliance: Ensure your email adheres to all SMTP standards
What email marketers say
13 marketer opinions
When email campaigns fail spam filter tests for older Outlook versions, marketers suggest several actions. First, assess the relevance of older Outlook clients in your audience; it might not be worth optimizing for a tiny fraction of users. Testing tools may be inaccurate, so send tests directly to Outlook inboxes. Address rendering issues by using tables and inline CSS, and avoid complex CSS or Javascript. Email authentication (SPF, DKIM, DMARC) is vital, and content should be checked for spam trigger words. Optimize images and include alt text, and maintain a clean email list. Finally, preview emails with tools like Litmus or Email on Acid to ensure correct rendering in Outlook.
Key opinions
- Audience Assessment: Determine the significance of older Outlook users in your target audience.
- Rendering Issues: Older Outlook versions often struggle with complex HTML and CSS.
- Email Authentication: Proper email authentication (SPF, DKIM, DMARC) is crucial for deliverability.
- Content Optimization: Avoid spam trigger words and optimize images for better filtering results.
- List Hygiene: Maintaining a clean email list helps maintain your sender reputation.
- Testing: Use email testing tools and send test emails directly to Outlook inboxes.
Key considerations
- Client Relevance: Is optimizing for older Outlook clients worth the effort given their prevalence?
- Rendering Techniques: Employ table-based layouts and inline CSS for better compatibility.
- Authentication Protocols: Implement SPF, DKIM, and DMARC to improve email deliverability.
- Content Scrutiny: Review email content to eliminate potential spam triggers.
- Sender Reputation: Continuously monitor and maintain a positive sender reputation.
- Testing Tools: Invest in email testing tools to identify and resolve Outlook-specific issues.
Marketer view
Email marketer from Mailjet shares the importance of setting up email authentication protocols (SPF, DKIM, DMARC) to improve deliverability and avoid spam filters. Missing authentication can be a red flag for older email clients.
3 Apr 2023 - Mailjet
Marketer view
Email marketer from HubSpot shares that maintaining a good sender reputation is crucial for email deliverability. Factors like sending volume, spam complaints, and bounce rates affect your reputation.
21 Jun 2023 - HubSpot
What the experts say
2 expert opinions
Experts advise that if email campaigns fail spam filters in older Outlook versions, be aware that these versions use the Word rendering engine, which has limited CSS support and can trigger spam filters. Using inline styles and testing tools are recommended. Email authentication is crucial for modern deliverability, but a holistic approach, including content and list hygiene, is still essential as older clients may not fully support these protocols.
Key opinions
- Outlook Rendering: Older Outlook versions utilize the Word rendering engine, leading to CSS limitations and potential spam triggers.
- Inline Styles: Using inline styles is recommended for better compatibility with older Outlook versions.
- Email Authentication: Email authentication (SPF, DKIM, DMARC) is critical for modern deliverability.
- Holistic Approach: A holistic approach, including content and list hygiene, is essential for older clients.
Key considerations
- Testing Tools: Use email testing tools to preview and test emails in older Outlook versions.
- CSS Support: Minimize CSS complexity due to the limitations of the Word rendering engine.
- Protocol Support: Understand that older clients may not fully support modern email authentication protocols.
- Content and List: Focus on content optimization and maintaining a clean email list.
Expert view
Expert from Word to the Wise (Laura Atkins) shares that while email authentication (SPF, DKIM, DMARC) is critical for modern email deliverability, older email clients may not fully support these protocols, and thus, a holistic approach, including content and list hygiene, is essential.
30 Jun 2023 - Word to the Wise
Expert view
Expert from Spamresource explains that older versions of Outlook use the Word rendering engine, which has limited CSS support, and can be triggered as spam. They recommend using inline styles and testing with tools like Litmus or Email on Acid.
27 Nov 2021 - Spamresource
What the documentation says
5 technical articles
Official documentation provides insight into addressing email deliverability issues related to spam filters and old Outlook versions. Microsoft highlights that Outlook users can adjust their junk email protection levels. Spamhaus advises checking and removing your IP from their blocklist if necessary. RFC Editor details the SMTP standards crucial for email servers. DMARC.org and DKIM.org emphasize the importance of DMARC and DKIM for email authentication, preventing spoofing and enhancing deliverability.
Key findings
- Outlook Settings: Users can customize junk email filtering levels in Outlook.
- Blocklist Status: Check and remove your IP from blocklists like Spamhaus.
- SMTP Standards: Adherence to SMTP standards is critical for email deliverability.
- Email Authentication: DMARC and DKIM are essential for preventing spoofing and improving deliverability.
Key considerations
- User Customization: Users having different junk email filtering settings can impact deliverability.
- IP Reputation: Monitor and maintain a clean IP reputation to avoid blocklists.
- Standard Compliance: Ensure your email server adheres to SMTP standards.
- Implementation: Implement DMARC and DKIM correctly to authenticate emails effectively.
Technical article
Documentation from DKIM.org describes DKIM and the signing of emails to improve email authentication.
22 Dec 2021 - DKIM.org
Technical article
Documentation from DMARC.org describes DMARC and its role in email authentication. Implementing DMARC helps protect your domain from spoofing and phishing attacks, improving deliverability.
12 Nov 2023 - DMARC.org
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