Thx to @Lilias to for his notice of the missing part in the command mentioned here:

Whonix Qubes/Reinstall How to Reinstall Qubes-Whonix TemplateVMs.

The command should be changed from:

sudo qubes-dom0-update --enablerepo=qubes-templates-community --action=upgrade <qubes-template-package>

it should be

sudo qubes-dom0-update --enablerepo=qubes-templates-community-testing --action=upgrade <qubes-template-package>

from qubes-templates-community to qubes-templates-community-testing

shall it be corrected in the wiki?