How To Upgrade Magento 2.3.x To Magento 2.4.x Enterprise-Edition / Commerce Cloud Edition

There are following below steps need to follow to Upgrade Magento version 2.3.x To Magento version 2.4.x for Enterprise-Edition / Commerce Cloud Edition

[1] – Take Project files & database backup

[2] – Install PHP 7.4, Mysql 5.7, Magento 2.4 also supports Mysql 8.0

[3] – Insall Elasticsearch 7.10

Check Elasticsearch working fine or not by command

curl -XGET 'http://localhost:9200'

[4] – Put site into maintenance mode by below command at Magento 2.3.x root

php bin/magento maintenance:enable

[5] – Take a backup of the composer.json by below command at Magento 2.3.x root path

cp composer.json composer.json.bak

[6] – Install the Composer update plugin by below command at Magento 2.3.x root path

composer require magento/composer-root-update-plugin=~1.0 --no-update

composer update

[7] – Update composer.json file with latest version. In our case, it is Magento Version 2.4.x

by below command at Magento 2.3.x root path

composer require magento/product-enterprise-edition=2.4.x --no-update

x = display 0,1,2,3,4, put as per your need

This command will take some time & actually download all the required
packages and upgrade your Magento version from 2.3.x to 2.4.x

composer update

[8] – Finally run below command at Magento 2.3.x root path

php bin/magento cache:clean
rm -rf var/cache/*
rm -rf var/page_cache/*
rm -rf generated/code/*
php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy -f

[9] – Disable maintenance mode run below command at Magento 2.3.x root path