Title: compatibility issue with PHP 8
Last modified: April 14, 2022

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# compatibility issue with PHP 8

 *  [fnctamp](https://wordpress.org/support/users/fnctamp/)
 * (@fnctamp)
 * [4 years, 1 month ago](https://wordpress.org/support/topic/compatibility-issue-with-php-8/)
 * Bonjour
    When I delete an article on this site, the deletion works but I get 
   this error message : `Warning: Undefined property: WP_Post::$filter in /datas/
   yulpa171734/sites/teplitz-theatre.net/htdocs/wp-includes/class-wp-post.php on
   line 342
 * Warning: Cannot modify header information – headers already sent by (output started
   at /datas/yulpa171734/sites/teplitz-theatre.net/htdocs/wp-includes/class-wp-post.
   php:342) in /datas/yulpa171734/sites/teplitz-theatre.net/htdocs/wp-includes/pluggable.
   php on line 1355
 * Warning: Cannot modify header information – headers already sent by (output started
   at /datas/yulpa171734/sites/teplitz-theatre.net/htdocs/wp-includes/class-wp-post.
   php:342) in /datas/yulpa171734/sites/teplitz-theatre.net/htdocs/wp-includes/pluggable.
   php on line 1358`
 * This appears only with PHP 8.0 when reverting to PHP 7.4, no more messges. Deactivating
   all plugins no messages. The culprit plugin is WP Super Cache. So there is an
   uncompatibility Super Cache and PHP 8
    Is there a solution or have I to change
   my cache plugin ?
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fcompatibility-issue-with-php-8%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 5 replies - 1 through 5 (of 5 total)

 *  Plugin Author [Donncha O Caoimh (a11n)](https://wordpress.org/support/users/donncha/)
 * (@donncha)
 * [4 years, 1 month ago](https://wordpress.org/support/topic/compatibility-issue-with-php-8/#post-15564000)
 * Thanks for reporting this. I haven’t had a chance to test in PHP8.0 yet so I 
   don’t know what the fix might be.
 *  Thread Starter [fnctamp](https://wordpress.org/support/users/fnctamp/)
 * (@fnctamp)
 * [4 years, 1 month ago](https://wordpress.org/support/topic/compatibility-issue-with-php-8/#post-15564223)
 * So will you test that and fix it ? Quickly ? If you do, I’m waiting because I
   like super cache. But I cannot wait long. Thank you
 *  Plugin Author [Donncha O Caoimh (a11n)](https://wordpress.org/support/users/donncha/)
 * (@donncha)
 * [4 years, 1 month ago](https://wordpress.org/support/topic/compatibility-issue-with-php-8/#post-15564287)
 * I think this is a WordPress core issue. I found [this ticket](https://core.trac.wordpress.org/ticket/54736)
   describing the problem.
    WP Super Cache uses get_sample_permalink() which unsets
   $post->filter.
 * I would not display errors on a production site. You should send them to an error
   log. While the warning will still be created it won’t interfere with how your
   site works.
 *  Thread Starter [fnctamp](https://wordpress.org/support/users/fnctamp/)
 * (@fnctamp)
 * [4 years, 1 month ago](https://wordpress.org/support/topic/compatibility-issue-with-php-8/#post-15564490)
 * Sorry, but you cannot say that is a WordPress issu. It happens only with super
   cache activated and with no other plugin. So it is indeed a super cache issue,
   even if doesn’t display on the frontend and even if it doesn’t interfer with 
   how the site works, what is true. It is your job to change that, with the wordpress
   team if you want. I hope you will be able to do so. When not, there will be more
   and more users with this issue when upgrading to PHP 8
 *  Plugin Author [Donncha O Caoimh (a11n)](https://wordpress.org/support/users/donncha/)
 * (@donncha)
 * [4 years, 1 month ago](https://wordpress.org/support/topic/compatibility-issue-with-php-8/#post-15564583)
 * I’m quite sure other plugins use get_sample_permalink(). They’ll have the same
   problem. I would love to fix this bug but I can’t, sorry.
 * I’m sure it will be fixed in the next release of WordPress.

Viewing 5 replies - 1 through 5 (of 5 total)

The topic ‘compatibility issue with PHP 8’ is closed to new replies.

 * ![](https://ps.w.org/wp-super-cache/assets/icon-256x256.png?rev=3506220)
 * [WP Super Cache](https://wordpress.org/plugins/wp-super-cache/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/wp-super-cache/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/wp-super-cache/)
 * [Active Topics](https://wordpress.org/support/plugin/wp-super-cache/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/wp-super-cache/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/wp-super-cache/reviews/)

 * 5 replies
 * 2 participants
 * Last reply from: [Donncha O Caoimh (a11n)](https://wordpress.org/support/users/donncha/)
 * Last activity: [4 years, 1 month ago](https://wordpress.org/support/topic/compatibility-issue-with-php-8/#post-15564583)
 * Status: not resolved