Title: WordPress 2.5 Upgrade error Last modified: August 19, 2016 --- # WordPress 2.5 Upgrade error * [spanishfry](https://wordpress.org/support/users/spanishfry/) * (@spanishfry) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/) * I’ve just tried to upgrade my WordPress from 2.2 to 2.5 and now when I try and go to my site ([http://arsenalfcblog.com](http://arsenalfcblog.com)) it comes up with the following message: * Fatal error: Call to undefined function: _http_build_query() in /home/arsenalf/ public_html/wp-includes/functions.php on line 628 * Any ideas? Viewing 9 replies - 1 through 9 (of 9 total) * [arieladams](https://wordpress.org/support/users/arieladams/) * (@arieladams) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746767) * I have having the same exact error. I need help! Why do the upgrade instructions have no troubleshooting section? Any help would be appreciated. * [moshu](https://wordpress.org/support/users/moshu/) * (@moshu) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746769) * What troubleshooting do you need? Every “undefined function…” error tells you about missing or corrupted file(s). The file where the claimed function is defined– is not there on your install or is demaged. * Upload a fresh copy of the WP files. And if you need to know the function is defined in wp-includes/compat.php * Thread Starter [spanishfry](https://wordpress.org/support/users/spanishfry/) * (@spanishfry) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746801) * Thanks for your help moshu – unfortunately I’ve tried uploading a fresh batch of WP files and I’m still getting the same problem. Is there something specific about the ‘line 628’ reference in the fatal error? * Is it possible that some of my plugins could be interfering? If not I’m quite lost, my site has been down for over 8 days trying to solve this problem and it is starting to get a little desperate… * Is there anything else you think I should try? Cheers in advance. * [moshu](https://wordpress.org/support/users/moshu/) * (@moshu) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746807) * Plugins? No plugins should be ever active during an upgrade, according to the instructions. * Thread Starter [spanishfry](https://wordpress.org/support/users/spanishfry/) * (@spanishfry) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746848) * OK – well I was just asking… * Have you any other ideas then because I’m lost as to what the solution is… * [tignarius](https://wordpress.org/support/users/tignarius/) * (@tignarius) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746850) * I have the same problem but mine is complicated by the fact that I was unable to gain access to the admin area of my 2.3 installation so was not able to de- activate the plugins….. Is this now going to be a big problem? * The host server was attacked and corrupted and the hosting company took two weeks to clean up the files but it somehow left my blog screwed-up so that I could not login to admin. That is why I tried to ungrade without deactivating the plugin the only one of which was installed was Akismet….. I think! * [tignarius](https://wordpress.org/support/users/tignarius/) * (@tignarius) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746853) * I am still without a resolution on this * [whooami](https://wordpress.org/support/users/whooami/) * (@whooami) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746854) * > I have the same problem but mine is complicated by the fact that I was unable > to gain access to the admin area of my 2.3 installation so was not able to > de-activate the plugins….. Is this now going to be a big problem? * It has said the same thing on the bottom of the plugins page since 2.0.x * **If something goes wrong with a plugin and you can’t use WordPress, delete or rename that file in the wp-content/plugins directory and it will be automatically deactivated.** * Are you not able to FTP? * [tignarius](https://wordpress.org/support/users/tignarius/) * (@tignarius) * [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746856) * Now we get to here…. Warning: main(C:\Inetpub\vhosts\scotsheraldry.com\httpdocs/ wp-settings.php): failed to open stream: No such file or directory in C:\Inetpub\ vhosts\scotsheraldry.com\httpdocs\wp-config.php on line 20 * Fatal error: main(): Failed opening required ‘C:\Inetpub\vhosts\scotsheraldry. com\httpdocs/wp-settings.php’ (include_path=’.;./includes;./pear’) in C:\Inetpub\ vhosts\scotsheraldry.com\httpdocs\wp-config.php on line 20 Viewing 9 replies - 1 through 9 (of 9 total) The topic ‘WordPress 2.5 Upgrade error’ is closed to new replies. ## Tags * [fatal error](https://wordpress.org/support/topic-tag/fatal-error/) * In: [Installing WordPress](https://wordpress.org/support/forum/installation/) * 9 replies * 5 participants * Last reply from: [tignarius](https://wordpress.org/support/users/tignarius/) * Last activity: [18 years, 1 month ago](https://wordpress.org/support/topic/wordpress-25-upgrade-error/#post-746856) * Status: not resolved ## Topics ### Topics with no replies ### Non-support topics ### Resolved topics ### Unresolved topics ### All topics