If you want to upgrade Magento version you need following steps.
Backup your Magento store:
Creating backups for your Magento 2 site is so urgent and necessary that you can protect all data from the disappearance through Backup Management if there is any change or break on the site. Follow this guide to backup your Magento 2 store.
You need on Your maintenance mode:
You should put your store in maintenance mode while upgrading. To enable maintenance mode:
php bin/magento maintenance:enable
It will create a new file var/.maintenance.flag. If you cannot disable maintenance mode, you can remove this file [Remmember!]
Upgrade to your Magento version:
In this case, I will upgrade to Magento version 2.2.1. See latest releases at to read more just click here. https://www.magemonkeys.com/how-to-upgrade-magento-version-from-2-3-2-to-2-3-5/