Title: Warning [PHP]
Last modified: September 1, 2016

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# Warning [PHP]

 *  [gersveo](https://wordpress.org/support/users/gersveo/)
 * (@gersveo)
 * [9 years, 9 months ago](https://wordpress.org/support/topic/warning-php/)
 * **Warning**: Parameter 1 to W3_Plugin_TotalCache::ob_callback() expected to be
   a reference, value given in /var/www/html/wp-includes/functions.php on line 3597
 * [https://wordpress.org/plugins/w3-total-cache/](https://wordpress.org/plugins/w3-total-cache/)

Viewing 1 replies (of 1 total)

 *  [Kimberly](https://wordpress.org/support/users/amiga500/)
 * (@amiga500)
 * [9 years, 9 months ago](https://wordpress.org/support/topic/warning-php/#post-7675159)
 * What follows is a list of files with line #s that you will need to change.
    Change**&
   $buffer** to be **$buffer**. So you are removing the ampersand (**&**).
 *     ```
       WP_PATH\wp-content\plugins\w3-total-cache\lib\W3\PgCache.php:331
       WP_PATH\wp-content\plugins\w3-total-cache\lib\W3\Plugin\BrowserCache.php:116
       WP_PATH\wp-content\plugins\w3-total-cache\lib\W3\Plugin\Cdn.php:242
       WP_PATH\wp-content\plugins\w3-total-cache\lib\W3\Plugin\Minify.php:131
       WP_PATH\wp-content\plugins\w3-total-cache\lib\W3\Plugin\NewRelic.php:31
       WP_PATH\wp-content\plugins\w3-total-cache\lib\W3\Plugin\TotalCache.php:512
       ```
   
 * And welcome to PHP7

Viewing 1 replies (of 1 total)

The topic ‘Warning [PHP]’ is closed to new replies.

 * ![](https://ps.w.org/w3-total-cache/assets/icon-256x256.png?rev=1041806)
 * [W3 Total Cache](https://wordpress.org/plugins/w3-total-cache/)
 * [Frequently Asked Questions](https://wordpress.org/plugins/w3-total-cache/#faq)
 * [Support Threads](https://wordpress.org/support/plugin/w3-total-cache/)
 * [Active Topics](https://wordpress.org/support/plugin/w3-total-cache/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/w3-total-cache/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/w3-total-cache/reviews/)

 * 1 reply
 * 2 participants
 * Last reply from: [Kimberly](https://wordpress.org/support/users/amiga500/)
 * Last activity: [9 years, 9 months ago](https://wordpress.org/support/topic/warning-php/#post-7675159)
 * Status: not resolved