Moving Off Legacy in a Regulated Business Without Breaking It
CIO, Wednesday, October 7th, 2026
A CIO explains how regulated migrations succeed by proving the new system matches old outcomes, guarding against 'quiet' failures.
Drawing on migrations from a VAX minicomputer running a parking operator's 200 New York City sites and a global fintech payments and card issuing core, a CIO.com author explains why regulated migrations fail differently.
Loud failures take systems down, as when TSB's 2018 big-bang migration locked customers out and led to a GBP 48.65 million fine, while quiet failures such as pricing discrepancies, missed filings or lost audit trails may not surface for weeks.
Not breaking the business means proving at every step that the new system produces the same outcomes as the old one.