Unsupported software and systems should not be used because fixes to newly identified bugs will not be implemented by the vendor. The lack of support can result in potential vulnerabilities.
Software and systems at unsupported servicing levels or releases will not receive security updates for new vulnerabilities, which leaves them subject to exploitation.
When maintenance updates and patches are no longer available, software is no longer considered supported and should be upgraded or decommissioned.
Check
Verify the DNS server is a version supported by the vendor.
If the DNS server is not a version supported by the vendor, this is a finding.
Fix
Install a version of the DNS server that is supported by the vendor.