[wp-trac] [WordPress Trac] #52822: PHPMailer change in WordPress 5.7 breaks working sites

[WordPress Trac]

#52822: PHPMailer change in WordPress 5.7 breaks working sites
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 Reporter:  tigertech                |       Owner:  (none)
     Type:  defect (bug)             |      Status:  new
 Priority:  high                     |   Milestone:  5.7.1
Component:  Mail                     |     Version:  5.7
 Severity:  normal                   |  Resolution:
 Keywords:  needs-patch 2nd-opinion  |     Focuses:
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Changes (by audrasjb):

 * keywords:   => needs-patch 2nd-opinion
 * priority:  normal => high


Comment:

 Hello, thanks for reporting this issue,

 I think #52822 is indeed a top priority issue for 5.7.1.

 Some hosting companies reached out to me to explain their concerns about
 the new PHPMailer version and all the potential issues that currently
 occur with WP 5.7. Some of them blocked the 5.7 update.

 When we updated the PHPMailer external lib in 5.7, maybe we should have
 made a (somewhat big) change on how WordPress manage its default emails
 (and perhaps our best bet is to provide a setting to set a specific email
 address for WordPress emails).

 By the way, that’s not a valid approach for a point release.

 I’m not a specialist of PHPMailer, but for 5.7.1, I can see several
 options:
 - Find a way to override PHPMailer settings
 - Directly edit the PHPMailer lib (this is not something we want)
 - Rollback PHPMailer to its previous version (same as above!)

 For more context, after a quick search, I think the issue comes from this
 upstream function:
 https://github.com/PHPMailer/PHPMailer/blob/master/src/PHPMailer.php#L1263

 (the new default value of the third parameter - $auto = true: I can’t tell
 why but it looks like the issue is related to this change)

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Ticket URL: <https://core.trac.wordpress.org/ticket/52822#comment:4>
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