What to ask your agency about legacy modernisation

The gap between knowing this and actually doing it is where most teams lose ground. If you are briefing an agency or a freelancer on legacy modernisation, these questions are worth asking early.

Most systems fail at the seams rather than inside any one component. The practical test is whether someone new to the project could tell, in a minute, that it had been handled.

Questions worth asking

• Who will actually do this work, and have they done it before?
• How will we know afterwards whether it worked?
• What happens if it needs changing in a year?
• What are you assuming that we have not confirmed?

What a good answer sounds like

Strangle the old system gradually rather than replacing it at once. That sounds obvious written down. It is still the thing most often skipped. It rarely shows up as a line item, which is exactly why it slips.

Every migration needs a way back. Where this goes wrong is almost never a lack of knowledge. The version that survives contact with a real deadline is the simple one.

What this looks like day to day

Architecture is the set of decisions that are expensive to reverse, which is the only reason they deserve the name. Three things worth confirming about legacy modernisation before you move on:

• Someone can say what the current setup is without going to look
• Every migration needs a way back — and you know whether that is true here
• There is a way to tell whether the last change to this helped

If any of that sounds like a description of your current setup, it is fixable.