The verdict in three sentences
A legacy application (PHP/jQuery, obsolete framework) should never be rewritten in one block: the big bang is the leading cause of failure for projects above 50,000 EUR. The strangler fig method — replacing module by module while keeping the existing system in production — cuts risk and spreads the budget over 6 to 12 months. Budget 40,000 to 120,000 EUR depending on scope, versus 1,000 to 3,000 EUR/month to keep a dying app that no one dares touch alive.
What a modernization costs in 2026
Price depends on the number of modules, the data volume to migrate and the accumulated technical debt. Here are the 2026 orders of magnitude seen in the Dubai market.
| Scope | Modules | Timeline | Budget |
|---|---|---|---|
| Partial (front-end) | 2-3 key screens | 3-4 months | 40,000-55,000 EUR |
| Core business refactor | 5-8 modules | 6-8 months | 60,000-90,000 EUR |
| Full rebuild + data | 10+ modules | 9-12 months | 90,000-120,000 EUR |
| Audit + migration plan only | — | 3-5 weeks | 6,000-12,000 EUR |
The upfront audit is not optional: it reveals the real debt. A 2013 app often hides dead dependencies, unindexed SQL queries and zero automated tests.
Strangler fig vs big bang: the risk trade-off
The big bang rewrites everything then switches over at once. Appealing on paper, disastrous in practice: for 8 months you pay two teams, scope drifts, and on go-live day nothing behaves like the old system. The strangler fig inserts a routing layer that sends each feature to either the old or the new system.
| Criterion | Big bang | Strangler fig |
|---|---|---|
| Disruption risk | High | Low |
| Value delivered | At the end (month 10) | Continuous (from month 2) |
| Rollback possible | No | Yes, per module |
| Double-run cost | 100 % | Spread, partial |
| Observed failure rate | ~40 % | ~12 % |
| Cash flow | Shock | Smoothed |
Data migration is the hard part: plan an idempotent script, a cutover environment and a reconciliation window. For 200,000 customer records, budget 3 to 6 days of dev and testing.
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Mini case study
Mark, IT director of a distribution SME in Dubai, runs a home-grown ERP on PHP 5.6. Maintenance cost: 2,200 EUR/month (legacy hosting + on-demand contractor), or 26,400 EUR/year with zero improvements. He chooses a strangler fig rebuild at 74,000 EUR over 8 months, module by module. From month 3, the modernized orders module saves his sales-admin team 6 hours a week. Over 3 years he saves the legacy maintenance (79,200 EUR) plus productivity gains: the rebuild pays back in 14 months.
FAQ
How long before the first results? With strangler fig, the first modernized module goes live as early as month 2 or 3, versus 10 months for a big bang. Value arrives progressively.
Can we keep the old app running in parallel? Yes, that is the whole point. The routing layer lets old and new systems coexist throughout the migration, typically 6 to 12 months, with no downtime for users.
What happens to the existing database? It is migrated in batches with a reversible script. For a mid-size volume (100,000 to 300,000 rows), migration + reconciliation takes 3 to 6 dedicated days.
What does doing nothing cost? Keeping a legacy app alive costs 1,000 to 3,000 EUR/month, rises every year, and the risk of a critical outage with no one to fix it becomes unmanageable beyond 8-10 years.
Must everything be rewritten in the same language? No. A rebuild is the chance to move to a maintainable stack (TypeScript, a modern framework), but not all at once: high business-value modules come first.
Let's scope your project. Describe your app (language, module count, data volume) and we will propose a costed strangler fig migration plan, with an indicative budget of 40,000-120,000 EUR. 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.
