Signs it is time to revisit legacy modernisation

We end up explaining this on discovery calls often enough that it deserved writing down. A few signals that legacy modernisation is due some attention.

Most systems fail at the seams rather than inside any one component. It is worth deciding this deliberately rather than inheriting whatever the last person set up.

The signals

• Nobody can say when it was last reviewed
• The answer depends on who you ask
• Strangle the old system gradually rather than replacing it at once
• Big-bang rewrites are the most reliable way to lose two years

The practical version

Every migration needs a way back. The teams that handle this well are rarely the ones with the biggest budgets. It is the sort of thing that looks like polish right up until it costs you an enquiry.

How to tell if yours is fine

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

Worth checking on your own setup before it becomes someone else's problem to fix.