Install the Shopware Conflicts Package: This page explains why you should add the shopware/conflicts metapackage to your project and how it automatically keeps known-incompatible dependency versions out of your installation.
Patching the Core: This page explains, how to use the Composer package cweagans/composer-patches to patch Shopware 6 core modules.
How to Discover Available Updates?: This page describes how to discover whether updates are available for any Symfony or Shopware component or any third-party plugin.