upgrade magento 2

bin/magento maintenance:enable
composer require magento/product-community-edition 2.2.0 --no-update
composer update
rm -rf var/cache/*
rm -rf var/page_cache/*
rm -rf var/generation/*
chmod +x bin/magento
bin/magento setup:upgrade
 php bin/magento setup:di:compile
bin/magento maintenance:disable

For further upgrades, change the version number:

composer require magento/product-community-edition 2.2.2 --no-update


rm -rf pub/static var/cache var/page_cache
rm -rf var/cache
rm -rf var/page_cache
rm -rf var/view_preprocessed

 php bin/magento cache:clean
  php bin/magento cache:flush

php bin/magento setup:static-content:deploy -f

php bin/magento module:status      -- to check activated modules




Step 1: Access Your Server via SSH

You need to connect your server via SSH.

Step 2: Navigate to the Magento 2 Root Directory

Once your SSH connection is up, you will need to move to your target application folder. In that application folder, you will find the public_html folder which is the root directory of Magento 2.

Step 3: Upgrade Commands

composer require magento/product-community-edition 2.1.9 --no-update

Then execute this all commands

 composer update
 rm -rf var/di var/generation
 php bin/magento setup:upgrade
 php bin/magento setup:di:compile
 php bin/magento cache:clean
 php bin/magento cache:flush
 php bin/magento indexer:reindex

 php bin/magento module:status

 php bin/magento module:disable <ExtensionProvider_ExtensionName>
 php bin/magento module:disable Prince_Buynow
 - php bin/magento module:disable SR_CategoryImage
 - php bin/magento module:disable Clapcreative_CategoryImage
 - php bin/magento module:disable Atwix_CategoryAttribute
 - php bin/magento module:disable Livenation_HelloWorld

 php bin/magento deploy:mode:show

 php bin/magento deploy:mode:set production --skip-compilation

 php bin/magento deploy:mode:set developer --skip-compilation


chmod -R 0777 pub/static/
chmod -R 0777 var/cache/
chmod -R 0777 var/page_cache


add these 3 lines to show errors
ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);