IT leaders offer hard-earned advice on undertaking largescale legacy IT transformations based on years-long experiences bridging their businesses to a new era.

A core part of digital transformation is decommissioning legacy apps, upgrading aging systems, and modernizing the tech stack. Yet, as appealing as it is for employees to be able to use modern technologies, decommissioning and replacing systems is arduous for IT.
Legacy systems that have ‘tentacles into everything’
Need circumspect about which systems needed decommissioning and started by looking at ones that were customer facing.
Beautifying ERP
The decision to migrate from an over 25-year-old SAP ECC ERP system to S/4HANA was pretty clearcut for Ulta Beauty.
Modernization gotchas
When an organization is truly legacy, most will likely have very little documentation of how those systems can be supported.
Don’t put off decommissioning systems when modernizing
When you modernize, you must have a decommissioning strategy as part of the plan.

Based on cio.com story by Esther Shein, APRIL 7 2025