There still are developers building and extending applications using languages like COBOL, since banks and other such organizations rely on ancient systems to power their day to day businesses. Some of these systems are mission critical, so instead of building up new ones, that might fail or have bugs, they prefer to continue using these ancient systems.

It would seem, that even though upgrading to newer software can be a pain, and a risk, there are tools and methodologies out there to make this transition safe. The benefits of upgrading to newer systems would of course be considerable - ease of maintenance, ease of finding skilled developers etc.

I have not yet heard of companies that are aimed at providing this service. Do they exist?

  • My initial thought is that an outsider can't simply "upgrade" a piece of software safely unless they've built and/or maintained it long enough to know exactly how it's supposed to behave, but maybe some form of consultant guiding the existing maintainers could make this work. I look forward to the answers on this one.
    – Ixrec
    Commented May 12, 2015 at 21:57
  • 1
    I'm voting to close this question as off-topic because it is not a conceptual programming problem as defined in the help center.
    – user22815
    Commented May 12, 2015 at 22:26
  • Surely the heart of the question is 'why oh why don't people ever refactor old systems?' which would fit the 'development methodologies and processes' category
    – Ewan
    Commented May 13, 2015 at 10:19

2 Answers 2


I'd say there are plenty of companies that do this.

IBM for one big (400k+ people) one (I work there).

There are lots of old applications, some running on mainframes that haven't been touched in years, and now can't really be changed, ever. They could be replaced, but it is hard to replicate their function exactly without full test coverage. There are whole teams dedicated to making mainframe applications written decades ago talk to newer programs across REST calls or whatever is the latest craze and link in with the latest regulations, security requirements etc.


There are many companies that claim to provide "commercial off the shelf" (COTS) products that will replace your legacy systems. My observations:

  • If the system being replaced adheres strongly to some standard, then a COTS solution is likely to be a good fit. Examples are enterprise accounting, payroll and tax packages provided by companies like SAP, IBM and Oracle. There are also niche providers that cover specialist fields like hospital management, hotel management, conference management etc.
  • If your system comes close to adhering to a standard, consider changing your business to fit the COTS product. Legacy systems often contain logic and business rules that have not been used for years, sometimes making this a viable alternative.
  • If your legacy system is unique and cannot be bent to fit the package, you may need to customize the package. This is where it gets interesting.
    • The customization may be only for you. When the next upgrade comes out you may have to pay a small fortune to the vendor to port the customized code, and there is nowhere else to go to get the work done.
    • Adding new features is easy if the package supports the new functionality, but can be extremely expensive if not. If the new feature is a customisation just for you, see the previous point.
  • Most modern COTS products provide some sort of configuration language or extension callouts to Java or similar. You can find yourself trying to write applications in a severely constrained environment using a poorly designed custom language - not a pleasant task.
  • If you regularly need to employ contractors, are there any available that know your COTS product?

So yes, there are companies out there that do replace legacy software, but the current trend seems to be towards COTS packages.

  • I agree, I guess it because its easier to convince a company that a COTS can replace their system, than convince them they need to rewrite it. something they have presumably been resisting if they are in that position in the first place!
    – Ewan
    Commented May 13, 2015 at 10:17
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    @Ewan Yes, the best part of many COTS products is their sales brochure, backed by a team of silver-tounged salespeople. My experience with COTS products has not been a happy one.
    – kiwiron
    Commented May 13, 2015 at 10:23

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