Follow below steps for Upgrade Magento 2.1.9 To 2.2.0 or any new Version Using CLI. Replace 2.2.0 with the Magento version you want to upgrade.
Hope this we'll helps you on magento upgradetion.
i try exactly that but get:
Your requirements could not be resolved to an installable set of packages.
- The requested package magento/product-community-edition 2.2.2 exists as magento/product-community-edition[2.1.10] but
these are rejected by your constraint.
on composer update ... we have version 2.1.10 currently installed wich was also installed with composer