`update` with external name failed

[isc-jinywang]

I am trying to update a module, this module has <Name> and <ExternalName> in module.xml. I have installed the previous version of the module and confirmed it exists using list-installed, for example:

zpm:XYZ>list-installed
abc_external (abc) 1.0.0

When using external name , for example:
update abc_external 1.1.0 -path abc.tgz -verbose
This failed with error message:
Module abc_external has not been installed. Please use the install or load commands to install the module before calling update.

When using the original name , for example:
update abc 1.1.0 -path abc.tgz -verbose
This does not throw error.