couple of old Kaspersky Endpoint Security AVs with KSC 11 as a Security center refuses to update

[Dave sum]

Hello, we have encountered a situation where some Kaspersky Endpoint Security clients on certain users' PCs running version 11.0.1.xxxxx( 11.0.1.15919 and 11.0.1.90) are unable to perform software updates or database updates to the latest version, whereas KES version 11.0.0.6699 (an older version) with certain Kaspersky Network Agent versions like 10.5.1871 and 10.0.1131, can update without a hitch.

We have comb through the update logs and audit logs from KES. For user PCs that failed to run the update task, all update entries end with "No updates available," while for the versions that ran successfully the update entries have "Completed" status.
The Kaspersky Security Center (KSC) being used is 11.0.0.1131( is this too outdated ?) . KSC is installed on Windows Server 2012 R2. The license details installed on KSC are "Kaspersky Next EDR Foundations South-East Asia Edition. 100-149 Users, 1-Year Renewal Plus License"

We have already tried clearing the KSC update repository and redownload the repo but to no avail.

Thanks in advance