Many WordPress user alway will facing WordPress appear empty page after upgrade to newer version of WordPress, 1 of the reason is due to you do not disable plugin before upgrade it.
Refer to the step below, you may disable the plugin through MySQL database(PHPMyAdmin).
1. Login to PHPMyAdmin.
2. Look to your databases(eg. mickgenie_wordpress).
3. Look to table named wp_options as browse it.
4. Search for the option named active_plugins and edit the record.
5. Open a notepad, cut the detail from option value to the notepad, save it to the notepad.
6. Select Go button from PHPMyAdmin.
7. Go to your WordPress Page and login to administrator, now you should able to see the WordPress upgrade page.
8. If you would like to have the same plugin activate to your WordPress follow step 1-4 from PHPMyAdmin and cut the detail from your notepad to the option value.