Aaron Bertrand has a great explanation of how to plan for TLS 1.2 support in SQL Server:
It seems straightforward, but as of today, not all builds will enable you to rush out and convert to TLS 1.2 exclusively. Here is what I suggest for each set of builds (in addition to patching .NET Framework, SQL Server Native Client, ODBC, and JDBC on all machines)
A protocol change seems like a small thing, but it suddenly gets to be a big thing when services stop working.