The verdict in three sentences
Modernizing an obsolete application costs 45,000 to 180,000 CAD in Toronto in 2026, of which +20 % for data migration alone, over 4 to 8 months. The right approach is rarely a total rewrite in one block but the strangler-fig strategy, which replaces modules progressively without stopping production. The payoff is concrete: technical debt cut by 60 %, maintenance cost halved and a team trained on the new stack.
What modernization costs, item by item
A legacy rebuild is not a simple facelift. It touches architecture, data, security and operations. Here is the cost breakdown observed in Toronto for a medium-sized business application.
| Item | Share of budget | Range (CAD) |
|---|---|---|
| Audit & existing mapping | 8-12 % | 5,000 - 18,000 |
| Architecture redesign | 15-20 % | 9,000 - 36,000 |
| Module redevelopment | 35-45 % | 20,000 - 81,000 |
| Data migration | +20 % | 9,000 - 36,000 |
| Testing & acceptance | 10-15 % | 5,000 - 27,000 |
| Team training | 5-8 % | 3,000 - 14,400 |
| Total rebuild | 100 % | 45,000 - 180,000 |
Data migration is the most often underestimated item: cleansing, mapping, reconciliation and testing easily represent 20 % of the budget, sometimes more if the old system has no documented schema.
Strangler-fig vs big bang: the ROI of modernization
Two strategies compete. Big bang rewrites everything and switches over at once: maximum risk. Strangler-fig wraps the old system and replaces modules one by one: production never stops. Here is the numeric impact over 3 years.
| Indicator | No rebuild | Big bang | Strangler-fig |
|---|---|---|---|
| Initial cost | 0 | 150,000 CAD | 120,000 CAD |
| Outage risk | Rising | High | Low |
| Technical debt at 3 years | +40 % | -60 % | -60 % |
| Annual maintenance | 38,000 CAD | 18,000 CAD | 18,000 CAD |
| Time to value | Never | 6-8 months | 2-3 months |
Strangler-fig often costs less overall because it spreads the risk and delivers value from the first modules. Over 3 years, maintenance savings alone (20,000 CAD/year) repay a large part of the rebuild.
Mini case study
Mr. Nolan, IT director of a distribution SME in Toronto, runs a stock-management application from 2013 costing 42,000 CAD/year in fixes and outages. Every month, two production days are lost to bugs.
He launches a strangler-fig rebuild at 115,000 CAD over 6 months. By month 3, the stock module is modernized and the outages stop. At 12 months, maintenance drops to 20,000 CAD/year, saving 22,000 CAD per year. Added to the recovered production days, the return on investment is reached in under 4 years, with a technical base ready for the next decade.
Need a professional website?
Kolonell builds websites that attract clients, optimized for the Sénégalese market. Free quote in 2 minutes.
FAQ
Should we rewrite everything at once?
Rarely. Big bang concentrates all the risk on a single cutover. The strangler-fig strategy replaces modules progressively and keeps production running, for far lower risk.
Why does data migration cost so much?
Because it involves cleansing, mapping, reconciliation and testing. It represents about 20 % of the total budget, more if the old system has no documented schema.
How long does a rebuild take in Toronto in 2026?
Between 4 and 8 months depending on size and number of modules. Strangler-fig delivers value from 2-3 months, versus 6-8 months for a big bang.
Does a rebuild really cut maintenance costs?
Yes, typically by half. A modern, tested and documented base costs half as much to maintain as legacy accumulating emergency patches.
What happens to my team during the rebuild?
They are trained on the new stack, an item budgeted at 5-8 %. It is essential to avoid recreating a dependency and to maintain the application in-house afterwards.
Let's scope your project. Tell us about your current application, its maintenance cost and pain points, and we will price a strangler-fig rebuild between 45,000 and 180,000 CAD. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
