Magento 2.1.18 is the final 2.1.x release. After June 2019, Magento 2.1.x will no longer receive security patches, quality fixes, or documentation updates.
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Missing .gitignore files

Problem: missing .gitignore files

If you downloaded a compressed archive, there might have been missing .gitignore files that prevent the upgrade from completing properly. To apply our update, patch magento/magento-composer-installer then run composer update from your Magento installation directory.

The following figure shows an example of this issue when using the Setup Wizard.

Solution

To solve this issue:

  1. Log in to your Magento server as the Magento file system owner.
  2. Change to your Magento installation directory.
  3. Run the following commands in the order shown:

    1
    2
    
    composer update magento/magento-composer-installer
    composer update
    
  4. Try your upgrade again.
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