v20

Fixes:

• Delete the possible unexpected node resources before updating VMs.
  • When Azure Security Center is enabled in a subscription, Azure Security Monitoring extension will be installed in all VMs under this subscription. All VMs' information will contain a node resources. This node must be deleted before updating VMs. Otherwise, you will hit an error InvalidRequestContent.
  • About Azure Security Center, you can get more information here.
• Other minor fixes