wahs

use this plugin:
https://www.introsites.co.uk/33~html-wordpress-permalink-on-pages-plugin.html

Try this:
https://www.ads-software.com/support/topic/147118?replies=4#post-673065

It works for me. Some say don’t work.

Make sure you deactivate your plugins before upgrading.

I upgraded one of my site, deactivated plugins before upgrading without any problems.

Next, 2nd site, forgot to deactivate plugins, I got a blank page after upgrading. I have to rename my plugin folder, then create a new plugin folder, point your page to wp-admin/upgrade.php and follow the instructions…

Remember to delete the empty plugin folder, and rename back the old one.

Hope these helps.