Unity 6.0 LTS Support Ends in October 2026 — Upgrade Checklist to 6.3 LTS

1. Freeze one known-good project state

Create a clean source-control checkpoint or full project backup before changing the editor version. Keep the last working build, project settings and package manifest recoverable.

2. Inventory packages, plugins and editor tooling

List Asset Store packages, native plugins, render-pipeline packages, input/networking dependencies and custom editor tooling. Check compatibility before upgrading the editor rather than discovering blockers after conversion.

3. Run asset QA before the editor upgrade

Missing scripts, material references, oversized textures, broken prefab dependencies and collider assumptions are easier to diagnose before a version change adds another variable.

4. Upgrade a copy or branch, not the only project

Open a duplicated project or dedicated migration branch in the target editor. Let package and serialization changes settle there first, then compare against the known-good baseline.

5. Re-test prefabs, materials and render pipeline

Open representative scenes and inspect nested prefabs, material assignments, shaders, lighting, cameras and render-pipeline settings. Do not treat a successful editor launch as a successful migration.

Missing-material checklist →

6. Re-test physics and bounds

Verify colliders, triggers, Rigidbody behavior, layers and any code that depends on world-space bounds. Migration bugs often look like gameplay bugs until physics assumptions are checked directly.

Collider.bounds guide →

7. Re-test textures, memory and target builds

Check import overrides, compression, texture sizes and representative builds for the platforms you actually ship. Editor behavior alone does not prove the player build is healthy.

Texture-size audit →

8. Keep a rollback path until the new build is proven

Do not delete the old project state immediately after conversion. Keep the last known-good branch or backup until gameplay, saves, input, networking and release builds have passed your regression checks.