Zoom ensures compatibility between the VDI Host and VDI Plugin by using an "Internal version" for compatibility checks, allowing the VDI Workplace client to support older plugins and ensuring seamless updates even when plugin versions appear newer than the host. Below is more information on how Zoom defines compatibility between the p;ugin and the host
While Zoom recommends updating both the VDI host and the VDI Plugin to the same release, we are aware the update process typically requires updating the VDI Zoom Workplace client first before updating VDI Plugins. For this reason, the VDI Zoom Workplace client is compatible with older releases of the Zoom VDI Plugin.
This compatibility requirement has sometimes been summarized with the statement, "The version of the VDI Plugin must be equal to or less than the version of the VDI Host."
However, with Zoom's commitment to providing timely patch releases for security and bug fixes, that compatibility statement needs to be updated to explain how version checks for patch releases work.
The modified and more accurate statement for version compatibility is; "The version of the Zoom VDI Plugin must be equal or less than the Internal version of the VDI Zoom Workplace client and Zoom VDI Plugin."
The Internal Version can be found in the VDI backward compatibility article. Look for the Core Client section at the top of the VDI releases table and see the column labeled "Internal version". The version displayed in this Internal version column is the value the VDI host uses to check compatibility with the VDI Plugin.
Knowing the Internal version is used to check compatibility explains why VDI Plugin Management updates can download and install a new VDI Plugin release that might seem more significant than the VDI Host version.
An example would be that the VDI Plugin can be updated to version 5.16.16 even when the version of the VDI Zoom Workplace client is still version 5.16.12. The reason is that both VDI Plugin 5.16.16 and VDI Host 5.16.12 have an internal version of 5.16.10. So, while VDI Plugin 5.16.16 was released after VDI host version 5.16.12, both releases are compatible because the check uses the internal version.
Knowing the compatibility check is for the internal version allows you to confirm compatibility between the plugin and host before downloading and installing a new update. Just check the internal version to confirm the internal version is the same, and that the combination of host and plugin will be compatible.
Backward compatibility with older VDI Plugins is also supported. If the internal version of the VDI plugin is less than the internal version of the VDI host, the older VDI Plugin with the lower internal version will also be compatible with the VDI Host.