Upgrading from 3.9.2 to 4.0 localized version I've been logged out

I want to add that in mine local enviroment, where I have the nightly build install I’ve never been logged out, nor with beta and nor with RC 1&2.

I also was logged out and cannot access the site. I get a message;Fatal error: Class ‘WP_Session_Tokens’ not found in /home/jimleeon/public_html/offgridok.com/wp-includes/pluggable.php on line 879. I sure would like to be able to get back into the admin of my site. Any help would be appreciated.

Jimlee in your situation I think that there are some missing files, upload the 4.0 via ftp and you should solve the problem.

All upgrades to 4.0 will cause you to be logged out. This is normal.

It’s because of a security hardening change to the way that the cookies work. Old cookies will be invalidated. No worries though, simply log in and you’re fine.

Note that if you’ve been updating nightlies for a long time, then this happened to you one time in the past and you never noticed it. The change was put in quite a while back.

@jimlee : Your error message is a symptom of an incomplete update. Try a manual update, and be sure to upload ALL of the WordPress files. Specifically, you need every file in wp-admin, wp-includes, and all the files in the root like wp-settings.php as well.

thanx Otto, I’ll put this information on the tomorrow post in WordPress Italy Blog.

Thank you, Wolly. That was the problem. Remedied now, thanks.

Yahoo web hosting sent out this: “Important Announcement: Required Upgrade to WordPress version 3.9.2” and many people reported problems with blog and plug-ins not recovered etc. Is it better to upgrade to WP 4? Will I see any issues?