Multizone modernises legacy iOS and Android apps in two weeks, preserving your brand, fixing the security gaps, and meeting current App Store and Google Play standards. We then manage everything that keeps the app current, on a monthly subscription.
This page is for product managers, business owners, and brand directors who already know their app is the problem. It explains exactly what we do, how we do it, and what it costs.
Who this is for
You are responsible for a mobile app that:
- Was last significantly updated more than 18 months ago
- Looks dated next to your current website and marketing
- Has a sign-up or registration flow that does not meet current standards
- Has been flagged for App Store or Google Play compliance, or you suspect it will be
- Carries security vulnerabilities you have not fully audited
- Performs poorly on current iPhone, iPad or Android devices
And you have already concluded that an agency rebuild is too slow, too expensive, or too risky.
What modernisation includes
The two-week modernisation is a fixed scope. Every engagement includes the following:
Trusted open-source framework
A modernised iOS and Android app supporting current OS releases, running on phones, tablets and Apple Silicon Macs. Built on Flutter, an open-source framework that compiles a single codebase directly to iOS and Android.
Brand and feature preservation
Your visual identity and core feature set carry through. We do not redesign your branding without permission; we modernise the structure and look and feel of your app in a way which preserves core colours and themes.
Modern sign-up flows
Email, Apple ID and Google sign-in to current standards, with appropriate consent and privacy compliance.
Security audit
Every dependency reviewed, known CVEs resolved, legacy authentication and storage patterns brought up to current standards.
App Store and Google Play submission
We handle store listings, review responses and submission. 100% historic approval rate.
How AI-powered migration changes the economics
A traditional agency rebuild costs what it does because every screen, every flow, every API call is reimplemented from scratch by a developer reading old code and writing new code. That is the part we have automated.
Our AI migration engine reads your existing codebase, identifies the patterns it has seen before, and produces a modernised equivalent on a current cross-platform framework. Our team then reviews, fills in the edges, integrates anything bespoke, and ships the result. We are not asking the AI to invent your app. We are using it to do the mechanical translation that used to consume 80% of an agency's billed hours.
That is why we can quote two weeks, fixed price, and still take responsibility for the result.
For the technical buyer: we publish framework choices, supported source codebases and the human-in-the-loop review process on request. Ask during the discovery call.
What "managed service" actually means
Most app projects end at delivery. Ours starts there. After the modernised app ships, you move onto the monthly management subscription, which covers:
- App Store and Google Play compliance. New review requirements, policy changes and guideline updates handled proactively. You do not get the surprise rejection email.
- OS compatibility. Support for new iOS and Android releases as they ship, including beta channel testing where appropriate.
- Store screenshots. Refreshed for new device sizes when Apple or Google requires it. Marketing-composed promotional screenshots are out of scope; your marketing team is welcome to use our device screenshots as source material.
- Security monitoring. Ongoing CVE monitoring on every dependency, with patches issued and shipped under the subscription.
- App stability. We review crash reports from the App Store and Google Play consoles and from any beta users, and act on what they reveal. Backend infrastructure is out of scope; the subscription covers the app, not your servers.
You receive proactive updates without briefing a developer or running a project. If something genuinely needs your attention (a brand decision, a new feature ask) we surface it. Otherwise, the app simply stays current.
What modernisation is not
So you can decide whether we are the right fit:
- Not a redesign. If you want a brand-new product, we will scope that separately or refer you to a design partner.
- Not a feature build. Bespoke new features are out of scope for the two-week modernisation. They can be added under management or quoted as a separate phase.
- Not a low-code platform. We deliver a real, production-quality app you own, not a configuration in someone else's tool.
- Not suitable for every app. Highly bespoke or poorly documented apps may exceed the AI complexity threshold. The audit tells us (and you) before we commit.
Timeline
| Day | What happens |
|---|---|
| Day 0 | You accept the proposal. We send a one-page intake form. |
| Day 1–2 | AI audit and scope confirmation. You see what we plan to preserve, rebuild and add. |
| Day 3–12 | Migration. We share a working build at day 7 for early feedback. |
| Day 12–14 | Final review, revisions, store submission. |
| Day 14+ | Management subscription begins. |
The schedule above describes Advanced App. Sophisticated App engagements typically run to roughly day 21, the additional week accommodating the deeper UX work and feature additions; the audit confirms the schedule for your specific app.
Investment
Advanced App: from £4,995 for modernisation, plus £495 / month under the Maintain subscription.
Sophisticated App: from £7,995 for modernisation, plus £995 / month under Enhance.
Twelve-month minimum subscription. Annual prepayment unlocks subscription discounts that scale with term length; thirty-six-month commitments also waive the modernisation fee entirely.
Full pricing detail and worked examples are on the pricing page.
Get the audit before you decide.
Send us your App Store and Google Play links. We will tell you, in 24 hours, exactly what your app needs and what it would cost to fix. No commitment.
Frequently asked
- What frameworks do you migrate to?
- We use Flutter as our default migration target. One codebase, compiled directly to iOS and Android, full phone and tablet form-factor support, and the maturity to be safe for production. We were at the Flutter launch event at the Science Museum in London in 2018 and have shipped Flutter apps continuously since, including major platform apps with tens of thousands of end users. If you have a strong preference for a different stack we will discuss alternatives during the audit.
- What source codebases can you migrate from?
- We have migrated from Objective-C, Swift, Java, and Appcelerator Titanium/Alloy codebases. The AI complexity audit confirms feasibility before we commit.
- Do we keep the source code?
- Yes. You own the codebase. You can leave the management subscription at any time and the code is yours.
- Are you UK-based?
- Yes. Multizone is a UK limited company; delivery is from the UK.