If you want to upgrade to macOS Big Sur, you must first upgrade Zscaler Client Connector to version 2.2.4 or later.

Also, on macOS Big Sur devices, Apple requires password confirmation for the user's account before Zscaler Client Connector can install and trust the root certificate. As a workaround, certificates can be installed via MDM for trust.

To learn more, see the Security section of the macOS Big Sur release notes.