PHP Upgrade & Codebase ModernisationBring an old PHP application up to date, securely and step by step.
We upgrade PHP 5 and 7 applications to supported PHP 8 versions, modernise frameworks such as CodeIgniter or custom core PHP, fix security issues and add tests, without a risky rewrite.
- PHP 5/7 to PHP 8
- Laravel modernisation
- Security fixed
- Modernisation Assessment2–3 weeks · Fixed price
- PHP Upgrade4–16 weeks · Fixed price per phase
How do you upgrade an old PHP application to PHP 8?
Start by auditing the code for deprecated functions, outdated libraries and security issues, then add tests around critical flows. Use automated refactoring tools to update syntax, upgrade dependencies and frameworks in steps, and test on the target PHP version before switching hosting. Stack18 upgrades legacy PHP applications this way and can move core PHP or CodeIgniter code into Laravel gradually.
- PHP 8 upgrade
- legacy PHP modernisation
- CodeIgniter to Laravel migration
- PHP 5 to PHP 8
- core PHP refactoring
Last reviewed 11 November 2026 by the Stack18 delivery team in Jaipur.Security & AI governancePricing
| What it covers | Code audit; Test safety net; Automated refactoring; Framework modernisation; Security hardening; Hosting and performance. |
|---|---|
| Typical first step | Modernisation Assessment: 2–3 weeks; fixed price. |
| Main engagement | PHP Upgrade: 4–16 weeks; fixed price per phase. |
| Measured by | Supported PHP version; Vulnerabilities fixed; Page load time; Error rate. Each against an agreed baseline. |
| Governance | Human approval at 5 governance gates before anything reaches production. NDA available on request. |
| Delivery team | Based in Jaipur, India. A senior specialist replies within one business day. |
You need this when…
Tap the ones that apply to you.
PHP Upgrade & Codebase Modernisation, end to end.
The features and building blocks of a PHP Upgrade & Codebase Modernisation engagement. Each is delivered by the same team on the Agentic SDLC, with your approval at every critical step.
Code audit
Deprecated code, libraries and risks found.
- Compatibility scan
- Dependency review
- Security findings
Test safety net
Tests around the flows that matter most.
- Critical path tests
- Regression suite
- Test environment
Automated refactoring
Syntax and APIs updated with tools.
- Rector refactoring
- Static analysis
- Coding standards
Framework modernisation
Core PHP or CodeIgniter moved towards Laravel.
- Gradual migration
- Routing and ORM
- Modern packages
Security hardening
Common vulnerabilities fixed.
- SQL injection fixes
- Input validation
- Secrets management
Hosting and performance
Modern hosting, caching and monitoring.
- Server upgrade
- Caching
- Error monitoring
A typical engagement, step by step.
Senior people lead every phase. Specialised AI agents on the Agentic SDLC handle the repetitive work, and nothing ships without your approval.
Discover
We map today’s process, systems and data for code audit, test safety net and automated refactoring, talk to the people who run it and agree the baseline for supported PHP version and vulnerabilities fixed, so progress is measured from week one.
Design
We design the flows, roles, approvals and integrations for code audit and test safety net, and review a clickable prototype or technical design with the people who will use it before anything is built.
Build
We build in weekly demos, starting with code audit, then test safety net and automated refactoring. Each release is tested on your own data and passes a human approval gate before the next begins.
Launch
We migrate data, train your team and support go-live. After 30 days we review supported PHP version and vulnerabilities fixed against the baseline and agree what to extend next.
How much does PHP Upgrade & Codebase Modernisation cost in India?
Most PHP Upgrade & Codebase Modernisation projects start with a Modernisation Assessment (2–3 weeks, fixed price), which fixes the scope, team and price before you commit. PHP Upgrade takes 4–16 weeks at a fixed price per phase. Prices exclude GST. Cloud hosting and third-party usage, such as messaging, payment or AI model charges, are paid at cost.
Modernisation Assessment
Teams deciding how to modernise a legacy system.
- Duration
- 2–3 weeks
- Pricing
- Fixed price
- Code and data review
- Options and costs
- Migration roadmap
PHP Upgrade
Teams with PHP 5 or 7 applications.
- Duration
- 4–16 weeks
- Pricing
- Fixed price per phase
- Upgraded codebase
- Test suite
- Security fixes
What drives the price
- Number of modules, workflows and user roles
- Integrations with your ERP, CRM, payments, GST or messaging tools
- Volume and quality of data to migrate
- Compliance, security and audit requirements
- Mobile apps, offline use or multiple languages
Always included
- Fixed scope and price before build starts
- Weekly working demos and human approval gates
- Training, documentation and 30 days of hypercare
- Your code, data and IP, owned by you
See Stack18 pricing or compare fixed price and time and materials.
What we have shipped, and what a typical engagement looks like.
Delivered projects link to the full case study. Illustrative scenarios describe typical engagements and are not named client results.
Real estate portal
- Challenge
- A PHP 5.6 core PHP site with frequent security alerts.
- What we do
- Audit, tests on key flows, upgrade to PHP 8 with automated refactoring and fixes for SQL injection risks.
- We would measure
- Supported PHP version, vulnerabilities fixed, page load time, against a baseline agreed in week one.
10 weeks
Distribution company
- Challenge
- A CodeIgniter 2 order portal could not move to new hosting.
- What we do
- Gradual migration to Laravel with tests, then a move to managed cloud hosting.
- We would measure
- Supported PHP version, vulnerabilities fixed, page load time, against a baseline agreed in week one.
14 weeks
Ethnic wear D2C, Jaipur
- Challenge
- A ₹100+ crore brand needed website, app and back office to share one catalogue and one record of stock and orders.
- What we do
- Nine specialists built website, mobile app and ERP on one connected foundation in two-week sprints.
3 months
Read the case study →We agree targets before we start.
Free PHP code health check
Give us read access. We report upgrade effort and risks.
- Compatibility report
- Security findings
- Effort estimate
Built for these industries.
PHP Upgrade & Codebase Modernisation questions.
Cost, timelines, integrations and ownership. If your question is not here, ask a senior specialist on a free 30-minute call.
Ask us anythingHow much does PHP Upgrade & Codebase Modernisation cost in India?
Most PHP Upgrade & Codebase Modernisation projects start with a Modernisation Assessment (2–3 weeks, fixed price), which fixes the scope, team and price before you commit. PHP Upgrade takes 4–16 weeks at a fixed price per phase. Prices exclude GST. Cloud hosting and third-party usage, such as messaging, payment or AI model charges, are paid at cost.
Should we rewrite instead of upgrading?
Usually not. Upgrading with tests keeps working business logic and is faster and less risky. We recommend a rewrite only when the code cannot be saved.
How long does a PHP upgrade take?
Small applications can take a few weeks; large ones a few months, depending on size and framework.
Will the site go down?
Upgrades are tested on a separate environment, and the switch is planned for minimal downtime.
Do you also upgrade WordPress?
Yes, including custom themes and plugins that break on newer PHP versions.
Do you provide PHP Upgrade & Codebase Modernisation across India?
Yes. Stack18 is headquartered in Jaipur, Rajasthan, and delivers PHP Upgrade & Codebase Modernisation for businesses across India, including Delhi NCR, Mumbai, Bengaluru, Pune, Hyderabad and Ahmedabad. Work runs remotely with weekly demos, and on-site workshops are arranged for key milestones.
Let's scope your PHP Upgrade & Codebase Modernisation project.
Tell us where you are and where you want to be. A senior specialist will reply within one business day with next steps.
- Free 30-minute consultation
- Indicative estimate after the call
- NDA available on request