COBOL 6 isn’t just a compiler upgrade—it’s your starting point for modern tools like watsonx Code Assistant for Z. COBOL 6 brings in powerful language features like JSON support, improved COBOL/Java interoperability, 31/64-bit compatibility, and the ability to work with unstructured data using VSAMDB. Plus, it helps you tap into the full performance potential of the IBM z/Architecture.

But upgrading isn’t just about switching to a newer compiler. It’s about making sure your long-standing COBOL code continues to run smoothly in today’s environment. That’s why the latest release of IBM COBOL Upgrade Advisor for z/OS version 1.1 includes a new feature that tackles one of the trickiest and most common upgrade headaches: invalid or uninitialized data.

Why does invalid data matter?

Upgrading from older versions like Enterprise COBOL 4.2 to COBOL 6 can reveal hidden issues that have quietly existed in production for years. One of the most common and disruptive problems is invalid or uninitialized data. These issues often stem from legacy coding practices that went unchecked under older compilers. But COBOL 6 introduces stricter runtime checks, which means what used to be silently ignored can now trigger runtime errors or unexpected behaviors. IBM estimates that roughly 25% of upgrade-related problems are tied to invalid data handling, making it a critical focus area for any modernization effort.

Meet the Invalid Data Detection Scan

To help developers catch these issues early, the COBOL Upgrade Advisor now includes an Invalid Data Detection Scan. This feature looks at runtime messages generated from invalid data detection compiler options such as NUMCHECK, PARMCHECK and SSRANGE and links them directly to the exact source line in your COBOL programs. It’s like flipping on a light switch—suddenly, those hard-to-spot data issues are easier to find and fix.

This new scan works alongside other CUAZ features like:

• Inventory analysis to get a clear picture of your codebase

• Upgrade readiness checks to flag potential blockers

• Compiler option suggestions for program consistency and compatibility when upgrading to COBOL 6

And it’s all available through a modern VS Code interface, making it easy to use whether you’re a COBOL veteran or just getting started.

Modern solutions for modern challenges

Invalid data issues can be tough to uncover and even tougher to resolve without the right tools. By building this detection right into the upgrade workflow, CUAZ helps teams reduce risk, speed up testing, and feel more confident about their modernization journey.

Whether you're upgrading for compliance, performance, or future-proofing, CUAZ now gives you a clearer view into your code and the hidden data behaviors that could cause trouble down the line.