Today, OpenText (the current owners) pushes for migration to modern platforms. But migration is expensive and risky. If a bank has a COBOL program calculating interest rates perfectly in a Net Express 5.1 wrapper, they have zero incentive to touch it—until the server crashes and they realize nobody has the installation media.
Micro Focus/OpenText does not offer this version on its current product download portal. Attempting to download from is: microfocus cobol net express 5.1 download
You must have an account with a Net Express entitlement on the OpenText Support Portal . Today, OpenText (the current owners) pushes for migration