Overview

After a Magento 2 upgrade to 2.4.8, many users reported issues with sending transactional or custom emails that included CSV attachments. This problem can severely impact order processing, reporting, and integrations with third-party systems. If you’re experiencing this issue, this comprehensive guide by a Magento enterprise developer outlines the causes and actionable fixes.

Common Symptoms

  • Emails are sent but the CSV attachment is missing.
  • Email logs show no errors, but attachments don’t appear.
  • MessageInterface implementations are failing silently.
  • The issue persists even after confirming email configuration is correct.

Root Causes

  1. Core Email Transport Changes in Magento 2.4.8
    • Magento has introduced changes in how MagentoFrameworkMailEmailMessageInterface handles attachments.
  2. Improper Mime Type Configuration
    • If the MIME type is not correctly set, the email may send without attaching the file.
  3. Missing Email Transport Builder Update
    • Custom modules or scripts may not be updated for compatibility with the new transport system.
  4. SMTP Extension Conflict
    • Some SMTP extensions are not fully compatible with the new message interface in Magento 2.4.8.

How to Fix the CSV Email Attachment Issue

1. Verify Code Uses EmailMessageInterface

Ensure your custom code or module uses the new EmailMessageInterface. Example:

Copy to Clipboard
2. Properly Define CSV Attachment in MIME Format

Make sure your attachment is structured correctly:

Copy to Clipboard
3. Use Compatible SMTP Modules

Use verified and Magento 2.4.8-compatible SMTP extensions such as:

Copy to Clipboard

Ensure the module version supports EmailMessageInterface.

4. Update Custom Modules for Compatibility

If you are using a custom module for sending emails:

Copy to Clipboard
5. Check Logs and Enable Developer Mode

Use the following to debug:

Copy to Clipboard

Best Practices Post Magento Upgrade

After any Magento upgrade service or custom development work, follow these practices:

  • Test all email flows including transactional and custom ones.
  • Use PHPUnit or integration tests to confirm functionality.
  • Keep all SMTP and email-related modules up to date.
  • Hire or consult a Magento enterprise developer for module audits.

Conclusion

The inability to send emails with CSV attachments in Magento 2.4.8 is often due to compatibility issues with new email service interfaces. Updating your modules and using the proper message interface will resolve the issue. For smoother transitions and minimal downtime, consider using a professional Magento upgrade service to ensure all features continue working post-upgrade.

We’re Ready to Help You

Contact us today for a free consultation and find out how our eCommerce and digital marketing services can transform your business.

Start Your Journey Today