Hey,
I’ve found a few older threads with a similar issue:
https://github.com/salesagility/SuiteCRM/issues/8808
https://community.suitecrm.com/t/upgrade-wizard-no-next-button/73576
https://community.suitecrm.com/t/button-next-dissapeared-from-upgrade-wizard/74349/2
General suggestions appear to be:
Resetting FIle/Folder Permissions, ie:
sudo chmod -R 755 .
sudo chmod -R 775 cache custom modules themes data upload
sudo chown -R www-data:www-data .
(replacing www-data with whatever your web server user is)
Or, if that fails, Some users have had success when attempting the Upgrade from 7.8.31 -> 7.10 LTS
However, they are rolling back and doing so without the Upgrade_patch installed
Do you have any success with either of these?
If not, please let us know, and I’ll set it up locally and give it a go