HI @a2usmani,
Are you running the upgrade via cli or browser?
If via cli, please use the command nohup php -d memory_limit=2048M upgrade.php upgrade inside the folder www/tools. When the error occur it will be registered in a file named nohup.out, please open the file with Vim and copy the error at the bottom of it. It’ll be a PHP fatal error.
Best,
Josh