Rewrites are where working software goes to die. There is a lower-risk path off legacy Informix 4GL: keep the business logic you trust, recompile it into Genero BDL, and modernize everything around it — one layer at a time.
The rewrite trap
A full rewrite asks you to reproduce decades of hard-won business rules — many of them undocumented, living only in the code — while the original keeps changing underneath you. Teams routinely underestimate that surface area, and the project stalls somewhere between “mostly done” and “can’t be switched off.”
The alternative is to treat the language, not the application, as the thing that needs to move forward.
What “recompile” actually means
Genero BDL is the direct evolution of the Informix 4GL language. Your existing
.4gl sources compile into Genero with little or no change, and the compiled
application runs on a maintained virtual machine — the same logic, now on a
platform that can reach the web, mobile, modern databases and open APIs.
Pick a single high-traffic screen, give it a modern UI, and ship it. You prove the pipeline on something small before you touch the core.
Modernize the layers, not the logic
Once the code is recompiled, you modernize deliberately:
- Interface — from character UI to graphical, web and mobile.
- Database — move off a single vendor at your own pace.
- Integration — expose typed APIs instead of screen-scraping.
- Deployment — containers and cloud when you’re ready, not before.
None of these require rewriting your business logic. That’s the point: the risk lives in the logic, so the logic is exactly what you don’t rewrite.
See how Genero Enterprise works