Heads Up :
The post you are writing will appear in a public forum. Please ensure all content is appropriate for public consumption. Review the employee guidelines for the community here.
That is true, there are a lot of things with upgrades in general; Security patches, configDB, Stats/ElasticDB, Yang changes etc..https://www.cisco.com/c/dam/en/us/td/docs/solutions/CVD/SDWAN/SD-WAN-End-to-End-Deployment-Guide.pdf(page 40)