updatd version of Magento to new one version

[scotlandki827a]

How can I update the old version of Magento ver. 2.4.0 to a new version Magento Commerce is 2.3. 4, if my website Scotland Kilt already exists on this platform, It's very difficult for me to do this, kindly help me out from this problem.
Thank you!

[Sanjay Jethva]

@scotlandki827a 

Take backup and update Magento

reference: https://devdocs.magento.com/guides/v2.4/comp-mgr/cli/cli-upgrade.html