magento 2.2 upgrade to latest version step by step instructions

The first step:

Before you do anything: go ahead and back up your store, we’ll need to back up the database and database, this should be a smooth upgrade but you never know (it’s Magento after all …) You will be grateful because you can downgrade to a functional version of Easily store your magento if an error occurs during the upgrade process. It’s important to back up your store for things like this, don’t underestimate the step!

You can do this with Magento CLI or, for your peace of mind, you may prefer to export the database manually.

We’ll assume you use a reasonable method to issue and maintain a magento store code base, such as GIT or SVN. We will be using GIT so we can create a new branch and use this branch to upgrade from Magento 2.2 to Magento 2.3 and test it before integrating it back into its main branch. Make sure to make a backup copy of composer.json on your warehouse.

 

The second step:

 

With the safely backed magento store, we can go ahead and start the upgrade process. It’s relatively easy in Magento 2 as most of it is processed by updating your composer file. This is generally done through the command line. Run the following commands to start the update process.

This will add new Magento 2.3 dependencies to your composer file:

 

This will add third party dependencies that the new 2.3 system uses:

This will remove some third party dependencies that are no longer used:

 

 

 

 

Now open the  composer.json  file and add  Zend\\Mvc\\Controller\\“: “setup/src/Zend/Mvc/Controller/  into the “psr-4” section.
The psr-4 section in your composer file should now look like the following: