This problem is related to the upgrade from ver. 3.9.* to version 4.
If you re-upload ONLY the wp-includes folder from a fresh download of WP v.4 then it should resolve the error.
Two installations of mine had been updated via the Softaculous auto-upgrade feature in cPanel. It may be related to their update script or it may be an error in the new WP version – I don’t know at this point.
Two installations of mine had been updated via the Softaculous auto-upgrade feature in cPanel. It may be related to their update script or it may be an error in the new WP version – I don’t know at this point.
There is no error in the download for this file as far as I can see.
Generally, I recommend against third party installers and upgraders for this exact reason: We know not what they do nor how they work. The built in auto-upgrade functionality in WordPress is better and more precise. I’d recommend using that, or doing upgrades manually. Avoid auto-updaters from other people.
If you want WordPress to auto-update itself even to new major versions, then it’s possible to turn that on too:
http://codex.wordpress.org/Configuring_Automatic_Background_Updates#Constant_to_Configure_Core_Updates
Can’t disagree Samuel, except to say that Softaculous is widely supported/included and regarded by many major hosting providers – I would expect that the problem IS here, but they are relatively swift to fix problems once they know about them.
Thanks for the link, will pass it on to clients.
