Application Modernization
Change the core without stopping the business
We move the systems a business depends on to foundations that can change, one slice at a time, while the old system keeps working.
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The problem
Most core systems are not broken. They are slow to change, expensive to keep and understood by fewer people every year. We replace them in slices, behind the same front door, so customers and staff notice only that things get faster.
A big-bang replacement asks a business to stop and hope. We prefer a route where every step is small enough to reverse, and every step pays for some of the next.
Old and new run side by side until the numbers match. Then the old part is switched off, and the people who will own the new one have been building it with us from the first week.
By the numbers
What standing still costs
- 61%
- of the average technology budget goes on keeping existing systems running, across the 140 engineering leaders we surveyed.
- 2 days
- is how long Halden Mutual now takes to settle a claim, down from nine, after replacing its claims core.
- 0
- planned business freezes across our last twenty modernization programs.
- 14 weeks
- from the first workshop to the first slice running in production, on average.
The maintenance dividend, KIASA research, 2026; KIASA program records, 2023 to 2026.
What we do
Modernization, one safe step at a time
Six kinds of work, usually combined. Each starts from what the business needs to change next, not from the technology.
Estate assessment
A map of every system, what depends on it, what it costs to run and how risky it is to touch. The first slice usually picks itself.
Slice-by-slice replacement
New services grow around the old core and take over its work one function at a time, behind the interfaces people already use.
Mainframe and legacy exit
Batch jobs, COBOL and decades of business rules, read carefully, tested against real history and moved without losing a single rule.
Data migration and reconciliation
Records moved in rehearsed waves and reconciled to the cent, with old and new compared every night until they agree.
Re-platforming to cloud
Applications moved to managed services where that lowers the cost and effort of running them, and left alone where it does not.
Code and architecture remediation
Tangled code untangled, tests added before changes, and the slowest parts of a system made fast enough to stop being a constraint.
Client work
Our work in action
Insurance
Halden Mutual replaced its claims core without a freeze
One product line at a time, over eighteen months. Claims now settle in two days, not nine.
Read the case study
Energy and utilities
Varda Energy reads two million meters without a mainframe
Thirty years of billing logic moved to services the team can change in an afternoon.
Read the case study
Banking and payments
Corrow Savings Bank moved its ledger off a 1990s core
Overnight batch replaced by posting in seconds, with the old ledger kept as a check for six months.
Explore banking
Public sector
Riverholt County Council retired four benefits systems for one
Caseworkers moved across in stages, team by team, without a single missed payment.
Explore public sector
What we think
Thinking on modernization
Research report
The maintenance dividend
Where the 61% goes, and how the best performers halve it by modernizing the systems that cost most to keep.
Perspective
Why the second year of a cloud migration matters more than the first
A migration is not finished at cutover. The second year decides whether the modernized system stays cheap to change.
Research report
Platform pulse: what engineering leaders will fund in 2027
Modernization is the line item 320 leaders are least willing to cut next year. Here is why.
Research report
Security debt: the quiet risk on the balance sheet
Old systems carry security debt. A way to price it into the case for replacing them.
“We expected a year of disruption. Instead we moved one product line at a time, and the only thing our customers noticed was that claims got paid sooner.”
How we work with you
From the first map to the last switch-off
Map the estate
Four weeks with your engineers and the people who use the systems. We leave with a costed map and a shortlist of first slices.
Choose the first slice
Small enough to ship in a quarter, valuable enough to matter, and close enough to the core to prove the route works.
Run old and new together
Both systems process the same work. We compare the results every night and switch over only when they agree.
Switch off and hand over
The old part is retired, its cost removed, and your team owns the new one. Then the next slice begins.
Our leaders
Talk to the people who lead this work
Duarte Moreira
Practice Lead, Application Modernization
Has led core replacements at insurers, banks and utilities for fifteen years, none of them with a freeze.
Aiko Tanabe
Principal Architect
Designs the seams where new services meet old cores, and the tests that prove both agree.
Kwabena Mensah
Head of Data Migration
Runs migration rehearsals until reconciliation is boring. Moved Varda Energy's two million meter records.
Ready to plan the first slice?
Tell us which system is slowing you down. A partner will reply within two working days with a first view of the route.