I got the same error as the one in this blog:
http://brucetank.blogspot.com/2017/10/biztalk-2016-wcf-custom-transport.html

System.Configuration.ConfigurationErrorsException: Unrecognized attribute 'ApplicationName'. Note that attribute names are case-sensitive. 

The difference is that I got it run-time, where in the blog above, he got it at the time of importing the bindings.

I was afraid that maybe the Cumulative Updates (CUs) were out of sync; and I have a project underway to make sure that both systems are on the latest CU6.

I tried removing the “ApplicationName = ”” out of the binding file and re-importing, but when I went to BizTalk Admin in my Production environment, the Application Name was there in the properties on the WCF-Custom (SQL) send port (and still had a blank value).

I looked for other differences between test and production, and discovered that I had switched it to a 64-bit Host Instance in Prod. When I switched it back to 32-bit Host Instance, it got past this issue.