Enabling the TLS 1.2 Only option on Safeguard, the setting is only configured on the Primary appliance.
Settings - Appliance - Appliance Information - TLS 1.2 Only - Enabled switch.
The TLS 1.2 setting needs to be enabled per appliance, and is not replicated from Primary to Replica.
A bug has been found in the Safeguard Desktop Client, the TLS 1.2 Only switch is greyed out when viewed from a Replica Appliance. Bug 231622 has been logged for this issue.
As a workaround it is possible to manually change the value in the Safeguard API: