Is BizTalk Server 2020’s WCF-SQL adapter supported for connecting to Azure SQL Managed Instance?

Microsoft’s published support matrix does not confirm Azure SQL Managed Instance as a supported external database target for BizTalk Server 2020’s WCF-SQL adapter, so this exact configuration should be treated as unsupported/unconfirmed unless Microsoft Support provides a written supportability statement for it.

Published support boundary

The two database roles are documented separately:

• BizTalk system databases: Azure SQL Managed Instance and other Azure PaaS database products are not supported for the BizTalk runtime databases. The Microsoft Q&A answer stating that BizTalk 2020 does not support SQL MI was specifically responding to a question about using MI for the BizTalk Runtime ^1^.
• External databases accessed through WCF-SQL: The BizTalk Server 2020 LOB support matrix explicitly says its SQL Server list applies to databases used by the WCF-SQL adapter, rather than BizTalk’s back-end databases. It lists SQL Server 2014, 2016, 2017, 2019, and Azure SQL Database—but not Azure SQL Managed Instance ^2^.

Consequently, the Q&A statement about MI cannot automatically be extended from BizTalk system databases to every external adapter connection. However, the separate WCF-SQL support matrix also does not identify MI as supported. Technical connectivity or successful testing would not by itself establish Microsoft product support.

For a production design requiring a support guarantee, open a Microsoft support request and ask for written confirmation covering:

1. BizTalk Server 2020 WCF-SQL/sqlBinding.
2. Azure SQL Managed Instance as an external LOB database.
3. The intended authentication method.
4. Polling and stored-procedure operations.
5. Local and distributed transaction patterns.
6. The exact BizTalk CU and SQL MI update policy.

Required BizTalk level for the proposed deployment

Because the BizTalk databases will remain on SQL Server 2022, BizTalk Server 2020 requires at least CU6. Microsoft also recommends installing the latest available updates for BizTalk, SQL Server, Windows, and related software. Microsoft OLE DB Driver for SQL Server 18.3.0 or later is required on all BizTalk Server computers ^3^.

The BizTalk Adapter Pack is included with BizTalk Server 2020 and does not require a separate installation ^2^.

No supplied Microsoft documentation identifies a CU, Adapter Pack update, or SQL client upgrade that adds explicit WCF-SQL support for SQL MI. Therefore, CU6 or a later CU satisfies the SQL Server 2022 back-end requirement but should not be interpreted as adding MI adapter support.

Authentication and adapter behavior

The documented WCF-SQL configuration supports:

• Windows authentication using the Windows identity recognized by SQL Server.
• SQL authentication using a database username and password.
• Enterprise SSO for supplying credentials.

These are selected in the adapter’s Security/Credentials configuration ^4^.

The documentation supplied here does not establish Microsoft Entra authentication, managed identity, or another MI-specific token authentication method for this adapter. Do not assume those methods are supported without confirmation from Microsoft Support.

WCF-SQL documents stored procedures, arbitrary SQL, composite operations, and Polling, TypedPolling, and XmlPolling against its supported SQL targets ^5^. These capabilities do not independently prove that the same operations are supported against MI.

For supported targets, polling uses the same transaction to execute the polling operation and submit the message to BizTalk when ambient transactions are enabled ^6^. That makes transaction compatibility a material concern, not merely basic TCP connectivity.

Network and transaction validation if Microsoft approves the design

If Microsoft confirms support, validate these conditions in a non-production environment:

• Use the MI VNet-local endpoint through VNet connectivity, peering, VPN, or ExpressRoute. The VNet-local endpoint uses its DNS name and port 1433; Microsoft advises using the domain name because the underlying address can change ^7^.
• Configure encrypted connectivity and certificate validation.
• For inbound polling, explicitly configure transaction isolation and timeout. WCF-SQL defaults and behavior can otherwise produce different locking characteristics than expected ^8^.
• If an operation enlists MI and another resource in one transaction, treat it as a distributed-transaction design. SQL MI DTC requires network connectivity and specific firewall ports; it also has authentication limitations ^9^.

The safest supported interim architecture is therefore to keep both BizTalk databases and WCF-SQL application targets on a SQL Server version explicitly listed for BizTalk 2020, or obtain a written Microsoft support exception/confirmation before placing the external OLTP databases on MI.

References

1. Biztalk 2020 support for SQL MI - Microsoft Q&A
2. Supported Line-of-Business (LOB) and Enterprise systems in BizTalk Server 2020
3. Hardware and Software Requirements for BizTalk Server 2020
4. Configure the connection URI for the SQL adapter
5. Key features in BizTalk Adapter for SQL Server - BizTalk Server
6. Polling in SQL Server using the SQL adapter
7. Connectivity architecture for Azure SQL Managed Instance
8. Configure Transaction Isolation Level and Transaction Timeout with SQL
9. Distributed Transaction Coordinator (DTC) for Azure SQL Managed Instance