CI3 to CI4 Migration
We specialise in migrating legacy CodeIgniter 3 applications to CodeIgniter 4 using a safe, structured, and zero-downtime approach. Our architecture-first methodology ensures your business continues running while your system is modernised for performance, scalability, and long-term maintainability.
The Challenge
Many businesses are stuck on CodeIgniter 3 with growing technical debt, security risks, and slower development cycles. A full rewrite is risky, and a poorly executed migration can break critical systems—especially in finance, payroll, or CRM platforms.
Our Engineering Process
Assess & De-risk
We audit your CI3 application, identify high-risk modules, and define a phased migration roadmap tailored to your business.
Migrate Incrementally
Using the Strangler Pattern, we migrate modules step-by-step while CI3 and CI4 run in parallel—ensuring zero downtime.
Validate & Optimise
We validate all outputs (especially financial logic), ensure data integrity, and optimise performance before final cutover.
What you get
- Zero-downtime migration strategy
- Full system audit & risk assessment
- Incremental module migration (Strangler Pattern)
- PHPUnit test coverage for critical logic
- CI3 to CI4 architecture redesign
- Secure API and integration handling
Typical deliverables
- Migration Roadmap & Architecture Plan
- Refactored CI4 Codebase (PSR-4 compliant)
- Automated Test Suite (PHPUnit)
- Updated Database & Models
- Deployment & Rollback Strategy
Best for
- Businesses running legacy CodeIgniter 3 applications
- Financial systems requiring high data accuracy
- Teams struggling with technical debt
- Companies planning long-term scalability
Why choose us
- Experience with complex legacy systems
- Strong focus on data integrity
- Architecture-first approach
- Proven migration strategy
Talk to us
Share your goals and constraints — we’ll suggest the most sensible next step.
Contact CuroByte