you can check below doc for clarification. Sp13 onwards proxy will contain multiple VDDK versions as part of VSA package install.
For each Commvault service pack, the Virtual Server Agent includes the latest supported VDDK.
For Commvault Version 11, Service Pack 13 and later, VDDK 6.0.2, VDDK 6.5, VDDK 6.5.2, and VDDK 6.7.1 are all included with the Virtual Server Agent. The appropriate VDDK for the vSphere version is loaded automatically when required. For more details, see VDDK Support for the Virtual Server Agent.
Customers can also update the VDDK manually. Do not place VDDK files in the VDDK installation in the Commvault base directory. Only install a newer version of the VDDK for proxies running on Windows. For Linux proxies, use a VDDK version that is included with the Virtual Server Agent package.
VDDK 5.5 or later is required for vSphere 5.5 support.
With VDDK 5.5 and later, 32-bit libraries and binaries are no longer supported.