Legacy projects - upgrade or replace?

Written by Olivér Haszpra

Why upgrade, why not replace?

Like it or not, it's not as easy to replace the old system as you might thought, because…

  • You don't know the specification
  • Probably there's no specification
  • The live system must be maintained during the new one's development phase
  • So you can't assign your existing team to the new project

Can't I replace?

Yes you can, but there will be challenges.

  • You'll need more workforce until the old system is discontinued
  • You'll need a very detailed specification for what exactly your system should do and how, which is often not known by anyone in the company

When to replace?

  • You have endless money to spend
  • You can't attract talented developers anymore with the old project
    • Developers like to play with fancy technologies
    • You want to attract talent with new technologies
  • The old system has too serious flaws to fix
  • New features would be too hard or impossible to implement in it
  • New UI/design would be too hard or impossible to implement in it

When to upgrade?

  • Flaws with the system are not that fatal
    • You still can hire good developers for it
    • Your customers / clients / employees like it
    • No bigger changes are necessary, you are in general happy with the system
  • You only need to add a little feature or bug fix here and there and the system doesn't prevent it
  • You don't have the resources necessary to build a new system from scratch
  • You don't have and can't really get the precise specification for the old or the new system

How to update, how to replace?

Read it in our next article.

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