1) >>Is this new version will be automatically available in Site24x7 dashboard?
If you have an On-Premise Poller already installed in your account, we will automatically upgrade to the latest version based on your upgrade settings.
To check your upgrade settings, click on the Settings icon available at the top right side of this page.
2) >> How do we check the version from the downloaded file?
Currently, it's not possible to check the version number in the downloaded file. We will add this to our roadmap.
3) >> Also maximum number of ESXi hosts or Vcenter servers can be monitored using one On-Premise poller?
Please refer to this page to know more about the minimum hardware requirement and the number of monitors we support.