Stuck on an old Unity version
You are on Unity 2019, 2020 or 2021. Builds are starting to fail on newer iOS or Android versions and third-party plugins are drifting out of compatibility.
Check your migration path
Legacy Game Modernisation, Flash to HTML5 and Unity Upgrades
Keep an established game playable and maintainable. We upgrade older Unity projects and rebuild games in unsupported technology, preserving the content and behaviour that matter.
Upgrading Domi Online from Unity 2021 to Unity 6.3
Developed by Ocean View Games as the client's core technical partner.
Domi is a live MMO with over 1,000 concurrent users. It uses FishNet for networking, a substantial custom render pass stack and Addressables for content delivery, and each of those introduced breaking changes across the 2021 to 6.3 gap.
We stepped the project through intermediate LTS releases, ran parity tests at each stage and rolled the new build out to closed beta before full release. No loss of concurrent users during the upgrade window, and no rollback.
An unfinished brief is fine. The first conversation helps establish scope.
What are you starting with?
This service fits three common situations. If any of these describes your project, we can help.
Built in unsupported technology
Flash, Java applets, early HTML5 frameworks or a custom 2000s engine. The game has proven demand but cannot run anywhere modern and needs a rebuild that preserves the content and audience.
See the Fire of London rebuildWorks, but needs new platforms
The source is older Unity, often PC-only, and you want to reach mobile or console. The project needs a supported Unity version and a modern build pipeline before the port can start.
Explore game portingThe three modernisation tracks
Most engagements are one of these, or a sequence that starts with one and ends with another.
1. Unity version upgrade
We upgrade Unity projects to a currently supported LTS release, stepping large gaps through intermediate versions so breaking changes are isolated and fixed at each stage.
2. Engine migration and rebuild
When the source technology is end-of-life, we rebuild the game against the original as a specification, preserving design, progression and player-visible behaviour. The target is usually Unity, but a Flash or Java title bound for the browser is often better served by an HTML5 rebuild, as with the Great Fire of London.
3. Modernisation with platform migration
Modernise the codebase to a stable foundation first, then port to the target platforms with the performance, input and UI work each one needs.
How we protect a live game during the move
We plan compatibility checks, gameplay comparisons and release safeguards around the existing game. This helps identify regressions before an upgrade reaches players.
1. Discovery and audit
A review of the project, dependencies, build and render pipelines, platform targets and analytics, delivered as a written report with the migration sequence, risk areas and timeline. Fixed-scope paid work, typically one to two weeks.
2. Compatibility staging
A branch on the target Unity version with package and plugin compatibility resolved and the automatic migration changes captured. Output is a clean build that compiles and runs, before gameplay parity is proven.
3. Parity testing
The modernised build run against the old build on matched scenarios: visual parity, gameplay behaviour, save data, networking and performance. Regressions are recorded, prioritised and reviewed against the agreed release criteria.
4. Platform and store validation
A rebuild for each live target platform, storefront compliance checks and testing on representative hardware. For live games this phase includes a rollback plan.
5. Staged release and monitoring
For live projects, a progressive release starting with a small percentage of users or a single platform, monitoring crash rates and performance before completing the rollout. Dormant projects collapse this into one launch step.
Our modernisation work
Rebuilds and upgrades delivered by Ocean View Games and its team.
Nub Remake
Java to Unity rebuild
The Challenge: Migrate an Ouya-era isometric puzzle game off native Java for iOS, Android and Steam.
The Result: A Unity rebuild across all three platforms with a touch control redesign for mobile.
Fire Of London
Flash to HTML5, during previous employment
The Challenge: Recreate the Museum of London's Great Fire game from a published Flash file with no source code.
The Result: An HTML5 rebuild that kept the educational content and returned the game to modern browsers.
What drives the cost and timeline
Every modernisation project quotes differently because scope varies so widely. These are the variables we weight most heavily.
Version gap
A single LTS jump is a fraction of the work of a four-version jump. Unity 2022 to Unity 6 is not Unity 2019 to Unity 6.
Render pipeline
Changing render pipeline can add substantial shader, material and lighting work. We assess it separately from the Unity version upgrade.
Third-party plugin count
Every abandoned or niche plugin is a potential blocker. Fifteen plugins is a different risk profile to three.
Platform target count
Each platform needs its own build validation, and mobile and console add certification overhead.
Live versus dormant
Live projects require parity testing, staged rollouts and rollback planning. Dormant projects can accept faster iteration.
Codebase quality
Projects with clean architecture modernise faster than projects carrying years of accumulated technical debt.
Working together
Start with a free conversation about what the project was built with, what still works and where you need it to run next.
Every engagement begins with a fixed-scope audit that produces a written migration plan, a risk assessment and a costed estimate for the scope identified. It is yours to keep whether or not we do the work; later changes to scope are agreed and priced separately.
David and Adam stay close to the engineering and technical decisions, and every engagement is led by a Unity Certified Expert. We can work alongside your own team where you have one.
Production runs in agreed milestones with regular builds, parity testing against the old version, and a staged rollout for anything live.
Meet the teamStart with the tools
Free tools to scope the work before we talk.
Unity Migration CheckerBreaking changes, deprecated APIs and a recommended migration sequence for your Unity version.Explore →Porting Feasibility CheckerWhether your game can move to a new platform and what that move involves.Explore →Game Development Cost EstimatorA ballpark budget for the full engagement.Explore →Porting Cost EstimatorA cost range if a platform move is part of the work.Explore →
Frequently Asked Questions
We assess the available source, playable builds, assets, dependencies and target platforms. The estimate separates investigation, rebuilding or upgrading, content recovery and testing. A scoped audit can establish the migration plan before you commit to implementation.
Sometimes. We first assess the published files, playable build and recoverable assets. During previous employment, our team recreated the Great Fire of London game in HTML5 from a published Flash file. The appropriate technology and feasibility depend on your project.
Yes. We rebuilt Nub from Java for Unity releases on iOS, Android and Steam. We use the original game as a behavioural reference and adapt controls and systems for the target platforms.
An upgrade retains the Unity project and adapts its code, assets and dependencies to a newer version. A rebuild recreates the experience on new foundations. We compare what can be retained, the risks and the maintenance needs before recommending either approach.
The version gap is only part of the work. Custom rendering, abandoned plugins, networking, save data and platform testing can all extend the timeline. We review those dependencies and provide a project-specific migration sequence and estimate.
We assess those decisions separately. Intermediate upgrades can help isolate breaking changes across a large version gap. A render pipeline change adds its own material, shader and lighting work, so we only include it when the project requirements justify it.
We check the versions and compatibility of your actual dependencies against the target Unity release. Where a plugin is unsupported, we identify whether it can be updated, replaced or removed and include that work in the plan.
Yes. We agree gameplay and save-data checks, release monitoring and rollback procedures around the live service. A staged release may be appropriate where the platform and infrastructure support it.
Need to modernise an older game or interactive?
Tell us what it was built with, what still works and where you need it to run next. We can help work out what should be upgraded, rebuilt or preserved.
Tell us about your project