I am trying to upgrade magento version from 2.1.8 EE to magento version 2.3.1. I am trying to update using command line procedure given here
At the step of Modify the Magento updater
I am getting the following error -
Could not find package magento/project-enterprise-edition with version 2.3.
I also tried to upgrade through script. It successfully upgraded from magento 2.1.8 EE to magento 2.3.1 EE through script on local setup , but not upgrading on server . The command to run the script just terminates showing no error on server instance.