Unity 6.3 LTS — Deprecated APIs

Last verified: 2026-09-12

Quick lookup table for deprecated APIs and their replacements. Format: Don't use X → Use Y instead

Input

Deprecated	Replacement	Notes
`Input.GetKey()`	`Keyboard.current[Key.X].isPressed`	New Input System
`Input.GetKeyDown()`	`Keyboard.current[Key.X].wasPressedThisFrame`	New Input System
`Input.GetMouseButton()`	`Mouse.current.leftButton.isPressed`	New Input System
`Input.GetAxis()`	`InputAction` callbacks	New Input System
`Input.mousePosition`	`Mouse.current.position.ReadValue()`	New Input System

Migration: Install com.unity.inputsystem package.

UI

Deprecated	Replacement	Notes
`Canvas` (UGUI)	`UIDocument` (UI Toolkit)	UI Toolkit is now production-ready
`Text` component	`TextMeshPro` or UI Toolkit `Label`	Better rendering, fewer draw calls
`Image` component	UI Toolkit `VisualElement` with background	More flexible styling

Migration: UGUI still works, but UI Toolkit is recommended for new projects.

DOTS/Entities

Deprecated	Replacement	Notes
`ComponentSystem`	`ISystem` (unmanaged)	Entities 1.0+ complete rewrite
`JobComponentSystem`	`ISystem` with `IJobEntity`	Burst-compatible
`GameObjectEntity`	Pure ECS workflow	No GameObject conversion
`EntityManager.CreateEntity()` (old signature)	`EntityManager.CreateEntity(EntityArchetype)`	Explicit archetype
`ComponentDataFromEntity<T>`	`ComponentLookup<T>`	Entities 1.0+ rename

Migration: See Entities package migration guide. Major refactor required.

Rendering

Deprecated	Replacement	Notes
`CommandBuffer.DrawMesh()`	RenderGraph API	URP/HDRP render passes
`OnPreRender()` / `OnPostRender()`	`RenderPipelineManager` callbacks	SRP compatibility
`Camera.SetReplacementShader()`	Custom render pass	Not supported in SRP

Physics

Deprecated	Replacement	Notes
`Physics.RaycastAll()`	`Physics.RaycastNonAlloc()`	Avoid GC allocations
`Rigidbody.velocity` (direct write)	`Rigidbody.AddForce()`	Better physics stability

Asset Loading

Deprecated	Replacement	Notes
`Resources.Load()`	Addressables	Better memory control, async loading
Synchronous asset loading	`Addressables.LoadAssetAsync()`	Non-blocking

Animation

Deprecated	Replacement	Notes
Legacy Animation component	Animator Controller	Mecanim system
`Animation.Play()`	`Animator.Play()`	State machine control

Particles

Deprecated	Replacement	Notes
Legacy Particle System	Visual Effect Graph	GPU-accelerated, more performant

Scripting

Deprecated	Replacement	Notes
`WWW` class	`UnityWebRequest`	Modern async networking
`Application.LoadLevel()`	`SceneManager.LoadScene()`	Scene management

Platform-Specific

WebGL

Deprecated	Replacement	Notes
WebGL 1.0	WebGL 2.0 or WebGPU	Unity 6+ defaults to WebGPU

Quick Migration Patterns

Input Example

// ❌ Deprecated
if (Input.GetKeyDown(KeyCode.Space)) {
    Jump();
}

// ✅ New Input System
using UnityEngine.InputSystem;
if (Keyboard.current.spaceKey.wasPressedThisFrame) {
    Jump();
}

Asset Loading Example

// ❌ Deprecated
var prefab = Resources.Load<GameObject>("Enemies/Goblin");

// ✅ Addressables
var handle = Addressables.LoadAssetAsync<GameObject>("Enemies/Goblin");
await handle.Task;
var prefab = handle.Result;

UI Example

// ❌ Deprecated (UGUI)
GetComponent<Text>().text = "Score: 100";

// ✅ TextMeshPro
GetComponent<TextMeshProUGUI>().text = "Score: 100";

// ✅ UI Toolkit
rootVisualElement.Q<Label>("score-label").text = "Score: 100";

Sources:

https://docs.unity3d.com/6000.0/Documentation/Manual/deprecated-features.html
https://docs.unity3d.com/Packages/com.unity.inputsystem@1.11/manual/Migration.html

Unity 6.3-Specific Additions (Deprecated APIs)

*Added 2026-09-12 from live WebSearch of the 6.3 LTS release notes and Upgrade Guide. The sections above cover the broad 2022 LTS → Unity 6 migration; this section covers deltas introduced in 6.3 itself, filtered for Iron & Timber (2D isometric, PC, single-player).*

Deprecated	Replacement	Notes
URP Render Pipeline Compatibility Mode	Render Graph	Compatibility Mode is fully removed in 6.3, not just deprecated. Any project or package still assuming it exists will fail.
`AccessibilityNode.selected`	`AccessibilityNode.invoked`	Old property still present but deprecated.
`AccessibilityRole` treated as a flags enum (bitwise combine)	`AccessibilityRole` as a standard (non-flags) enum	Bitwise operations now produce compiler warnings and can misreport to screen readers.
`Scene.handle` read/stored as `int`	`Scene.handle` as `SceneHandle` type	Binary compatibility break, not a soft deprecation — old serialized `int` handles will not round-trip correctly.
Legacy ETC texture compression setting	Default ETC compressor (auto-migrated)	Mobile-only concern; not relevant to the current PC-only target.
Multiplayer Widgets (UI package)	Unity Building Blocks	Not relevant — this project is single-player.

Watch List (not yet deprecated, but flagged by Unity as changing)

UI Toolkit USS validation is stricter, not deprecated — existing USS that compiled before may now surface parser errors. Treat any USS compile warning on upgrade as a real issue, not noise.
Shader Graph nodes under the old URP-only compiler path — no specific node is listed as removed, but the unified URP/HDRP compiler in 6.3 is new enough that any Shader Graph pattern copied from a pre-6.3 tutorial should be smoke-tested rather than trusted by default.

Sources

https://docs.unity3d.com/6000.3/Documentation/Manual/UpgradeGuideUnity63.html
https://unity.com/blog/unity-6-3-lts-is-now-available