When you tried to log in your wp-admin from your wordpress after a update, and you got “upgrade.php?_wp_http_referer=%2Fwp-admin%2F”.
Here is the super fast easy fix:
- Rename /Wp-content/plugins this folder to a random name , eg, plugins2
- Run http://xxx.com/wp-admin to update your database
- Rename back plugins2 to plugins
http://www.vashistha.in/2016/12/problem-solved-upgradephpwphttpreferer2.html