SMEX 12.0 and 12.5 can run in environments where only TLS 1.2 is enabled and .Net Framework 4.5 is installed. Know the details on TLS 1.2 support for SMEX.
SMEX 12.0 should apply Patch 2 for Service Pack 1 to be able to support TLS 1.2.
SMEX 12.5 supports TLS 1.2 by default.
To check whether your SQL Server can support TLS 1.2, refer to this guide on TLS 1.2 support for Microsoft SQL Server.