Legacy System Modernisation Issue Log
This is a practical guide to building a issue log for a legacy system modernisation project — a register of problems that have occurred and need resolving, adapted to the realities of modernising or replacing ageing core systems.
What a Issue Log is
A issue log is a register of problems that have occurred and need resolving. For the full concept and how it works in general, see Issue Log. On a legacy system modernisation project it plays the same role, tuned to this kind of work.
Why it matters for a Legacy System Modernisation project
Legacy System Modernisation projects live or die on modernising or replacing ageing core systems. A well-built issue log gives the team a shared, explicit reference for exactly that — reducing ambiguity, aligning stakeholders, and making problems visible early enough to act. Skipping it, or doing it generically, is how legacy system modernisation projects drift into avoidable delay and cost.
What to include
- Issue description
- Priority and severity
- Owner
- Resolution and status
Legacy System Modernisation-specific considerations
Tailor the issue log to the risks that most often derail legacy system modernisation projects:
- Undocumented legacy behaviour
- Phased cutover risk
- Knowledge loss
Example
On a real legacy system modernisation project, the issue log would be shaped by modernising or replacing ageing core systems. In particular, it should explicitly account for the project’s biggest risks — undocumented legacy behaviour, phased cutover risk, knowledge loss — rather than treating them as afterthoughts.