Search notes:

Registry: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\<VERSION>

Possible values of <VERSION> seem to be

SchUseStrongCrypto

SchUseStrongCrypto is a REG_DWORD that controls if strong cryptography (TLS versions 1.0, 1.1 and 1.2) is enforced.
Apps that target .NET Framework 4.6 or later defaults to the value 1.

SystemDefaultTlsVersions

SystemDefaultTlsVersions is also a REG_DWORD

Index