Title: Undefined function is_plugin_active() after update
Last modified: August 31, 2016

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# Undefined function is_plugin_active() after update

 *  [cypruscf](https://wordpress.org/support/users/cypruscf/)
 * (@cypruscf)
 * [10 years, 1 month ago](https://wordpress.org/support/topic/undefined-function-is_plugin_active-after-update/)
 * Fatal error: Call to undefined function is_plugin_active()
    …wp-content/themes/
   spacious/inc/header-functions.php on line 134
 * After updating theme to latest version conflict caused with “Seriously Simple
   Podcasting” plugin.
 * Thanks,
    Alex.

Viewing 3 replies - 1 through 3 (of 3 total)

 *  [Hugh Lashbrooke](https://wordpress.org/support/users/hlashbrooke/)
 * (@hlashbrooke)
 * [10 years, 1 month ago](https://wordpress.org/support/topic/undefined-function-is_plugin_active-after-update/#post-7258764)
 * Hi there,
 * I’m the author of Seriously Simple Podcasting. I’d be interested to know why 
   you think this is caused by a conflict with my plugin, especially because it 
   never calls the `is_plugin_active()` function once. If you could offer more info
   on why you believe the conflict is with Seriously Simple Podcasting then I’ll
   see what I can do to fix it from my side.
 * Cheers,
    Hugh
 *  Thread Starter [cypruscf](https://wordpress.org/support/users/cypruscf/)
 * (@cypruscf)
 * [10 years, 1 month ago](https://wordpress.org/support/topic/undefined-function-is_plugin_active-after-update/#post-7258771)
 * Hi Hugh,
 * Basically I believe the problem lies with the latest Spacious Theme and not the
   SSP plugin. After rolling back to the previous version of the theme, the problem
   disappeared.
 * I only got the aforementioned error when trying to view a podcast series (i.e.
   Archive page). The actual episode pages and podcast feed worked, as well as the
   rest of the website.
 * Thanks,
    Alex
 *  [Hugh Lashbrooke](https://wordpress.org/support/users/hlashbrooke/)
 * (@hlashbrooke)
 * [10 years, 1 month ago](https://wordpress.org/support/topic/undefined-function-is_plugin_active-after-update/#post-7258772)
 * Oh OK – then it definitely sounds like a theme issue. I’ll bow out as only your
   theme devs will be able to help from here on 🙂

Viewing 3 replies - 1 through 3 (of 3 total)

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## Tags

 * [undefined function](https://wordpress.org/support/topic-tag/undefined-function/)

 * 3 replies
 * 2 participants
 * Last reply from: [Hugh Lashbrooke](https://wordpress.org/support/users/hlashbrooke/)
 * Last activity: [10 years, 1 month ago](https://wordpress.org/support/topic/undefined-function-is_plugin_active-after-update/#post-7258772)
 * Status: not resolved