[wp-trac] [WordPress Trac] #64367: Upgrade to WordPress core 6.9 from 6.8.3 causes WooCommerce email failure?

[WordPress Trac]

#64367: Upgrade to WordPress core 6.9 from 6.8.3 causes WooCommerce email failure?
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 Reporter:  philipg100         |       Owner:  (none)
     Type:  defect (bug)       |      Status:  closed
 Priority:  normal             |   Milestone:
Component:  Mail               |     Version:  6.9
 Severity:  normal             |  Resolution:  duplicate
 Keywords:  reporter-feedback  |     Focuses:
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Comment (by jorbin):

 > is it down to the plugin developers to make their plugins compatible
 with 6.9?

 Yes. The expectation is that plugin developers test and ensure their code
 works with each version. If they believe they have found a bug, they
 should report it here. Everyone with a plugin hosted in the WordPress
 plugin repository recieves an email reminding them of this and
 highlighting changes. There is also a [https://make.wordpress.org/core/tag
 /field-guide/ field guide] published each release with most of the large
 changes. For example, you can read about the
 [https://make.wordpress.org/core/2025/11/18/more-reliable-email-in-
 wordpress-6-9/ email changes in 6.9], which may be causing your issue.

 The goal is for things to just work for everyone, but due to the infinite
 combinations of server configurations, it isn't possible for the volunteer
 contributors to test them all. That's why there are many calls for testing
 throughout the release cycle. For WordPress 6.9, there were
 [https://wordpress.org/news/category/releases/ 5 different calls for
 testing on WordPress.org/news (3 Release Candidates and 2 betas)].

 Thank you for joining in and trying to help debug this so that WordPress
 can be better for everyone. I would encourage you to share more about your
 specific server configuration and what your debugging finds on #64368.

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Ticket URL: <https://core.trac.wordpress.org/ticket/64367#comment:8>
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