Fatal error: Call to undefined function wp_is_mobile() in /home/content/15/77955

Can you post the full error message?

Fatal error:Call to undefined function wp_is_mobile() in /home/content/15/77955

Fatal error: Call to undefined function wp_is_mobile() in /home/content/15/7795515/html/wp-admin/index.php on line 22

Try replacing your index.php file located in your wp-admin directory with a new one.

Ok, I will try, How do I do that? Thanks!

What do I replace it with?

the call to wp_is_mobile on line 22 is correct…
It is defined around line 100 of vars.php in wp-includes folder… so it should be fine

Have you tried deactivating all plugins and switching to 2011 theme to test your site, in case of a conflict

Download the .zip of wordpress 3.4

Extract it to your computer, and use FTP or CPanel to overwrite the original.

REV, Can I deactivate from FTP File Manager on host site? I cant get to my dashboard at all.

Josh, I downloaded WP 3.4 so now I upload it to my File Manager? Will it automatically override whats there now?

Also, I see the upgrade in my root directory, what if I just delete it? Will it then revert back to the old version?

to deactivate all plugins at once, just rename the plugins folder to something else

wp-content -> plugins, I usually just rename to plugins.OLD

Make a new empty folder named plugins

Okay, then what? And how do I make a new folder?

HELP?? Anyone?? I really need to work on my site but I cant get in due to this error. I changed all plugins to plugins.old and nothing happened. I uploaded WP 3.4 and overwrote existing files in the upgrade and nothing. I am at a loss and VERY frustrated. And not very savvy when it comes to back-end WP stuff. Why would an upgrade cause this much trouble!?!?!

Having same problem.

I tried changing the plugins folder to a different name. That did not work.

Called GoDaddy. They could not help either.

Stuck and frustrated. Any help would be greatly appreciated.

What theme are you using?

Try using either FTP or CPanel to rename your current themes folder. This will force your WP installation to use the default theme.

It’s possible the themes you guys are using don’t provide support for the wp_is_mobile function.

1. Navigate to wp-content/themes.
2. Find the folder for your current theme, and rename it to something different.

Now, go back and try to log into your admin panel.