Without a specific post-release hotfix (KB 4057117 for SQLNCLI11), you cannot connect to a SQL Server instance that requires TLS 1.2. Even with the hotfix, modern servers may reject the older TDS protocol negotiation. 6. Migration Strategy Off of SQLNCLI If you are maintaining a legacy app and reading this to "fix a connection failure," you should migrate to a supported driver.

Provider=SQLNCLI11;Server=myServer\instance;Database=myDB;Trusted_Connection=yes;

Driver=SQL Server Native Client 11.0;Server=myServer;Database=myDB;Trusted_Connection=yes; | Issue | SQLNCLI10 (2008) | SQLNCLI11 (2012) | |--------|------------------|------------------| | TLS 1.2 | ❌ No | ❌ No (unless hotfixed) | | SHA-2 signed SQL Server certs | ❌ No | ❌ No (partial with hotfix) | | Azure SQL Database | ❌ Fails | ⚠️ Unsupported but may connect | | SQL Server 2022 | ❌ Fails | ❌ Untested, likely fails | | Windows 11 | ⚠️ Works but insecure | ⚠️ Works but insecure |

| Legacy Component | Modern Replacement | |------------------|--------------------| | SQLNCLI OLE DB | MSOLEDBSQL (Microsoft OLE DB Driver for SQL Server) | | SQLNCLI ODBC | ODBC Driver 17/18 for SQL Server |