There are three ways to upgrade Magento theme and modules. We use Composer for its flexibility and coonvenience.
Set my magento website to Developer Mode first.
bin/magento mode:set developer
Remove existing cached and generated files.
- rm -rf var/view_generated/*
- rm -rf var/cache/*
- rm -rf var/page_cache/*
- rm -rf generated/code/*
rm -rf pub/static