Ensure AS2 MDN Response is Not Affected by HTTP Accept Header

Hi Team,

I'd like to submit a feature request regarding AS2 (EDIINT) MDN handling in webMethods Integration Server.

Currently, when watt.server.http.useAcceptHeader=true, the Integration Server determines the response format based on the incoming HTTP Accept header. As a result, if the sender includes Accept: text/html, the AS2 MDN response may be altered to HTML format instead of the expected MIME multipart/report.

This issue specifically occurs for synchronous MDNs, where the MDN is returned in the HTTP response body.

From an AS2 protocol perspective, MDN messages are strictly defined as MIME multipart/report (or multipart/signed) and should not be subject to HTTP content negotiation. Therefore, the Accept header should not influence the MDN response format.

Additionally, we have confirmed that in webMethods 8.x, the system consistently returned valid MDNs regardless of the Accept header value. The behavior change observed in later versions suggests a potential regression or unintended side-effect of architectural changes in HTTP handling.

While we understand that the current architecture relies on the Integration Server HTTP layer, requiring the sender to modify the Accept header is not a practical solution in real-world B2B environments, where external partner systems are often not under our control.

This issue has the following impacts:

• AS2 partners may fail to process MDNs due to unexpected HTML content
• Potential compliance concerns with AS2 (RFC 4130) specifications
• Operational challenges in B2B environments due to limited control over partner systems
• The suggested workaround (watt.server.http.useAcceptHeader=false) is not viable, as it breaks REST API functionality by disabling content negotiation globally

Given the above, we would like to request the following:

• Provide a mechanism to ensure synchronous AS2 MDN responses are always generated in the correct MIME format, independent of the HTTP Accept header
• Alternatively, allow configuration to ignore the Accept header specifically for EDIINT/AS2 synchronous MDN processing

I believe this is important not only as an enhancement but also from a protocol compliance and backward compatibility perspective.

I would appreciate your consideration and prioritization of this request.

Best regards,
Sunjin Yim