I did an upgrade by installing a fresh 1.9.3.6 and then copied back my core files. Now i have a blank page and cant see any errors which make me think it is nearly there.
I looked in the server logs and found
mod_fcgid: stderr: PHP Fatal error: Uncaught Error: Function name must be a string in /var/www/vhosts/xxxxxxx/app/code/local/Mage/Core/Model/Layout.php:555
mod_fcgid: stderr: Stack trace:
mod_fcgid: stderr: #0 /var/www/vhosts/xxxxxxxxx/app/code/local/Mage/Core/Controller/Varien/Action.php(390): Mage_Core_Model_Layout->getOutput()
mod_fcgid: stderr: #1 /var/www/vhosts/xxxxxxxx/app/code/core/Mage/Adminhtml/controllers/IndexController.php(82): Mage_Core_Controller_Varien_Action->renderLayout()
mod_fcgid: stderr: #2 /var/www/vhosts/xxxxxxxxx/app/code/local/Mage/Core/Controller/Varien/Action.php(418): Mage_Adminhtml_IndexController->loginAction()
mod_fcgid: stderr: #3 /var/www/vhosts/xxxxxxxx/app/code/local/Mage/Core/Controller/Varien/Router/Standard.php(254): Mage_Core_Controller_Varien_Action->dispatch()
mod_fcgid: stderr: #4 /var/www/vhosts/xxxxxxxxxx/app/code/local/Mage/Core/Controller/Varien/Front.php(172): Mage_Core_Controller_Varien_Router_Standard->match()
mod_fcgid: stderr: #5 /var/www in /var/www/xxxxxxxxxx/app/code/local/Mage/Core/Model/Layout.php on line 555
I realize this is an old version but I wanted to get it to a newer 1.9 version then make the jump to v2.
The PHP version is 7.4.