The SAP .Net Connector (NCo) new build 3.0.21 is supported by the Cumulative Update 6 (CU6) for Microsoft BizTalk Server 2016.
Microsoft has added this support to the Microsoft products that are listed in the "Applies to" section.
This problem is fixed in the following cumulative update for BizTalk Server:
Cumulative Update 6 for BizTalk Server 2016
For information about the service packs and cumulative update list for BizTalk Server, see the following article in the Microsoft Knowledge Base:
2555976 Service pack and cumulative update list for BizTalk Server
For more information about BizTalk Server hotfixes, see the following article in the Microsoft Knowledge Base:
2003907 Information about BizTalk hotfixes and Cumulative Update support
Third-party information disclaimer
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.