diff --git a/packages/base/package.json b/packages/base/package.json
index 391fa6a6..b0fe2784 100644
--- a/packages/base/package.json
+++ b/packages/base/package.json
@@ -15,6 +15,8 @@
     "@pixi/math": "^6.1.0",
     "@pixi/mesh": "^6.1.0",
     "@pixi/mesh-extras": "^6.1.0",
+    "@pixi/runner": "^6.1.0",
+    "@pixi/settings": "^6.1.0",
     "@pixi/sprite": "^6.1.0",
     "@pixi/utils": "^6.1.0"
   },
diff --git a/packages/base/src/SpineBase.ts b/packages/base/src/SpineBase.ts
index de015fa8..53a346d2 100644
--- a/packages/base/src/SpineBase.ts
+++ b/packages/base/src/SpineBase.ts
@@ -4,7 +4,9 @@ import {TextureAtlasRegion} from './core/TextureAtlas';
 import {MathUtils} from './core/Utils';
 import type {
     IAnimationState,
-    IAnimationStateData,
+    IAnimationStateData
+} from './core/IAnimation';
+import type {
     IAttachment, IClippingAttachment, IMeshAttachment,
     IRegionAttachment,
     ISkeleton,
diff --git a/packages/base/src/core/IAnimation.ts b/packages/base/src/core/IAnimation.ts
new file mode 100644
index 00000000..74292755
--- /dev/null
+++ b/packages/base/src/core/IAnimation.ts
@@ -0,0 +1,136 @@
+import {ISkeleton, ISkeletonData} from './ISkeleton';
+import type {Map} from './Utils';
+
+// Those enums were moved from Animation.ts of spine 3.8 and 4.0
+
+/** Controls how a timeline value is mixed with the setup pose value or current pose value when a timeline's `alpha`
+ * < 1.
+ *
+ * See Timeline {@link Timeline#apply(Skeleton, float, float, Array, float, MixBlend, MixDirection)}.
+ * @public
+ * */
+export enum MixBlend {
+    /** Transitions from the setup value to the timeline value (the current value is not used). Before the first key, the setup
+     * value is set. */
+    setup,
+    /** Transitions from the current value to the timeline value. Before the first key, transitions from the current value to
+     * the setup value. Timelines which perform instant transitions, such as DrawOrderTimeline or
+     * AttachmentTimeline, use the setup value before the first key.
+     *
+     * `first` is intended for the first animations applied, not for animations layered on top of those. */
+    first,
+    /** Transitions from the current value to the timeline value. No change is made before the first key (the current value is
+     * kept until the first key).
+     *
+     * `replace` is intended for animations layered on top of others, not for the first animations applied. */
+    replace,
+    /** Transitions from the current value to the current value plus the timeline value. No change is made before the first key
+     * (the current value is kept until the first key).
+     *
+     * `add` is intended for animations layered on top of others, not for the first animations applied. Properties
+     * keyed by additive animations must be set manually or by another animation before applying the additive animations, else
+     * the property values will increase continually. */
+    add
+}
+
+/** Indicates whether a timeline's `alpha` is mixing out over time toward 0 (the setup or current pose value) or
+ * mixing in toward 1 (the timeline's value).
+ *
+ * See Timeline {@link Timeline#apply(Skeleton, float, float, Array, float, MixBlend, MixDirection)}.
+ * @public
+ * */
+export enum MixDirection {
+    mixIn, mixOut
+}
+
+/**
+ * @public
+ */
+export interface IAnimation<Timeline extends ITimeline = ITimeline> {
+    name: string;
+    timelines: Timeline[];
+    duration: number;
+}
+
+/**
+ * @public
+ */
+ export interface IAnimationState<AnimationStateData extends IAnimationStateData = IAnimationStateData> {
+    data: AnimationStateData;
+    tracks: ITrackEntry[];
+    listeners: IAnimationStateListener[];
+    timeScale: number;
+
+    update(dt: number): void;
+    apply(skeleton: ISkeleton): boolean;
+
+    setAnimation (trackIndex: number, animationName: string, loop: boolean): ITrackEntry;
+    addAnimation (trackIndex: number, animationName: string, loop: boolean, delay: number): ITrackEntry;
+    addEmptyAnimation (trackIndex: number, mixDuration: number, delay: number): ITrackEntry;
+    setEmptyAnimation (trackIndex: number, mixDuration: number): ITrackEntry;
+    setEmptyAnimations (mixDuration: number): void;
+    hasAnimation(animationName: string): boolean;
+    addListener (listener: IAnimationStateListener): void;
+    removeListener (listener: IAnimationStateListener): void;
+    clearListeners (): void;
+    clearTracks (): void;
+    clearTrack (index: number): void;
+}
+
+/**
+ * @public
+ */
+ export interface IAnimationStateData<SkeletonData extends ISkeletonData = ISkeletonData, Animation extends IAnimation = IAnimation> {
+    skeletonData: SkeletonData;
+    animationToMixTime: Map<number>;
+    defaultMix: number;
+    setMix (fromName: string, toName: string, duration: number): void;
+    setMixWith (from: Animation, to: Animation, duration: number): void;
+    getMix (from: Animation, to: Animation): number;
+}
+
+/**
+ * @public
+ */
+ export interface IAnimationStateListener {
+    start? (entry: ITrackEntry): void;
+    interrupt? (entry: ITrackEntry): void;
+    end? (entry: ITrackEntry): void;
+    dispose? (entry: ITrackEntry): void;
+    complete? (entry: ITrackEntry): void;
+    event? (entry: ITrackEntry, event: IEvent): void;
+}
+
+/**
+ * @public
+ */
+export interface ITimeline {
+}
+
+/**
+ * @public
+ */
+ export interface ITrackEntry {
+    trackIndex: number;
+    loop: boolean;
+    animationEnd: number;
+    listener: IAnimationStateListener;
+
+    delay: number; trackTime: number; trackLast: number; nextTrackLast: number; trackEnd: number; timeScale: number;
+    alpha: number; mixTime: number; mixDuration: number; interruptAlpha: number; totalAlpha: number;
+}
+
+/**
+ * @public
+ */
+export interface IEventData {
+    name: string;
+}
+
+/**
+ * @public
+ */
+export interface IEvent {
+    time: number;
+    data: IEventData;
+}
diff --git a/packages/base/src/core/IConstraint.ts b/packages/base/src/core/IConstraint.ts
new file mode 100644
index 00000000..c7242d00
--- /dev/null
+++ b/packages/base/src/core/IConstraint.ts
@@ -0,0 +1,104 @@
+
+// These enums were moved from PathConstraintData.ts of spine 3.7, 3.8 and 4.0
+
+/** Controls how the first bone is positioned along the path.
+ *
+ * See [Position mode](http://esotericsoftware.com/spine-path-constraints#Position-mode) in the Spine User Guide.
+ * @public
+ * */
+export enum PositionMode {
+    Fixed, Percent
+}
+
+/** Controls how bones are rotated, translated, and scaled to match the path.
+ *
+ * [Rotate mode](http://esotericsoftware.com/spine-path-constraints#Rotate-mod) in the Spine User Guide.
+ * @public
+ * */
+export enum RotateMode {
+    Tangent, Chain, ChainScale
+}
+
+/**
+ * @public
+ */
+export interface IConstraintData {
+    name: string;
+    order: number;
+}
+
+/**
+ * @public
+ */
+export interface IIkConstraint {
+    data: IIkConstraintData;
+    /** -1 | 0 | 1 */
+    bendDirection: number;
+    compress: boolean;
+    stretch: boolean;
+
+    /** A percentage (0-1) */
+    mix: number;
+}
+
+/**
+ * @public
+ */
+export interface IIkConstraintData extends IConstraintData {
+    /** -1 | 0 | 1 */
+    bendDirection: number;
+    compress: boolean;
+    stretch: boolean;
+    uniform: boolean;
+
+    /** A percentage (0-1) */
+    mix: number;
+}
+
+/**
+ * @public
+ */
+export interface IPathConstraint {
+    data: IPathConstraintData;
+    position: number;
+    spacing: number;
+
+    spaces: number[];
+    positions: number[];
+    world: number[];
+    curves: number[];
+    lengths: number[];
+    segments: number[];
+}
+
+/**
+ * @public
+ */
+export interface IPathConstraintData extends IConstraintData {
+    positionMode: PositionMode;
+    rotateMode: RotateMode;
+    offsetRotation: number;
+    position: number;
+    spacing: number;
+}
+
+/**
+ * @public
+ */
+export interface ITransformConstraint {
+    data: ITransformConstraintData;
+}
+
+/**
+ * @public
+ */
+export interface ITransformConstraintData extends IConstraintData {
+    offsetRotation: number;
+    offsetX: number;
+    offsetY: number;
+    offsetScaleX: number;
+    offsetScaleY: number;
+    offsetShearY: number;
+    relative: boolean;
+    local: boolean;
+}
diff --git a/packages/base/src/core/ISkeleton.ts b/packages/base/src/core/ISkeleton.ts
index 6000aa01..4574d8c0 100644
--- a/packages/base/src/core/ISkeleton.ts
+++ b/packages/base/src/core/ISkeleton.ts
@@ -1,31 +1,17 @@
 import {AttachmentType} from './AttachmentType';
+import {IAnimation, IEventData} from "./IAnimation";
+import {IIkConstraintData, IPathConstraintData, ITransformConstraintData} from './IConstraint';
 import type {Color, Vector2, Map} from './Utils';
 import type {TextureRegion} from './TextureRegion';
 
 import type {Matrix} from '@pixi/math';
 import {BLEND_MODES} from '@pixi/constants';
 
-/**
- * @public
- */
- export enum MixBlend {
-    setup,
-    first,
-    replace,
-    add
-}
-
-/**
- * @public
- */
- export enum MixDirection {
-    mixIn,
-    mixOut
-}
+// This enum was moved from BoneData.ts of spine 3.7, 3.8 and 4.0
 
-/**
+/** Determines how a bone inherits world transforms from parent bones.
  * @public
- */
+ * */
  export enum TransformMode {
     Normal,
     OnlyTranslation,
@@ -49,27 +35,7 @@ export interface ISkin {
     name: string;
     attachments: Array<Map<IAttachment>>;
 
-    setAttachment (slotIndex: number, name: string, attachment: IAttachment): void;
     getAttachment (slotIndex: number, name: string): IAttachment | null;
-    attachAll (skeleton: ISkeleton, oldSkin: ISkin): void;
-}
-
-/**
- * @public
- */
-export interface IAnimation {
-    name: string;
-    timelines: ITimeline[];
-    duration: number;
-
-    apply (skeleton: ISkeleton, lastTime: number, time: number, loop: boolean, events: Array<Event>, alpha: number, blend: MixBlend, direction: MixDirection): void;
-}
-
-/**
- * @public
- */
-export interface ITimeline {
-    apply (skeleton: ISkeleton, lastTime: number, time: number, events: Array<Event>, alpha: number, blend: MixBlend, direction: MixDirection): void;
 }
 
 /**
@@ -177,12 +143,15 @@ export interface ISlot {
 /**
  * @public
  */
-export interface ISkeleton<Bone extends IBone = IBone, Slot extends ISlot = ISlot, Skin extends ISkin = ISkin> {
+export interface ISkeleton<SkeletonData extends ISkeletonData = ISkeletonData,
+                           Bone extends IBone = IBone,
+                           Slot extends ISlot = ISlot,
+                           Skin extends ISkin = ISkin> {
     bones: Bone[]
     slots: Slot[]
     drawOrder: Slot[]
     skin: Skin;
-    data: ISkeletonData;
+    data: SkeletonData;
     updateWorldTransform (): void;
     setToSetupPose (): void;
     findSlotIndex (slotName: string): number;
@@ -209,101 +178,38 @@ export interface ISkeletonParser {
 /**
  * @public
  */
-export interface ISkeletonData {
+export interface ISkeletonData<BoneData extends IBoneData = IBoneData,
+                               SlotData extends ISlotData = ISlotData,
+                               Skin extends ISkin = ISkin,
+                               Animation extends IAnimation = IAnimation,
+                               EventData extends IEventData = IEventData,
+                               IkConstraintData extends IIkConstraintData = IIkConstraintData,
+                               TransformConstraintData extends ITransformConstraintData = ITransformConstraintData,
+                               PathConstraintData extends IPathConstraintData = IPathConstraintData> {
     name: string;
-    bones: IBoneData[];
-    slots: ISlotData[];
-    skins: ISkin[];
-    defaultSkin: ISkin;
-    events: IEventData[];
-    animations: IAnimation[];
+    bones: BoneData[];
+    slots: SlotData[];
+    skins: Skin[];
+    defaultSkin: Skin;
+    events: EventData[];
+    animations: Animation[];
     version: string;
     hash: string;
     width: number;
     height: number;
+    ikConstraints: IkConstraintData[];
+    transformConstraints: TransformConstraintData[];
+    pathConstraints: PathConstraintData[];
 
-    findBone(boneName: string): IBone | null;
+    findBone(boneName: string): BoneData | null;
     findBoneIndex(boneName: string): number;
-    findSlot(slotName: string): ISlot | null;
+    findSlot(slotName: string): SlotData | null;
     findSlotIndex (slotName: string): number;
-    findSkin (skinName: string): ISkin | null;
-    findEvent (eventDataName: string): IEventData | null;
-    findAnimation (animationName: string): IAnimation | null;
-}
-
-/**
- * @public
- */
-export interface ITrackEntry {
-    trackIndex: number;
-    loop: boolean;
-    animationEnd: number;
-    listener: IAnimationStateListener;
+    findSkin (skinName: string): Skin | null;
 
-    delay: number; trackTime: number; trackLast: number; nextTrackLast: number; trackEnd: number; timeScale: number;
-    alpha: number; mixTime: number; mixDuration: number; interruptAlpha: number; totalAlpha: number;
-}
-
-/**
- * @public
- */
-export interface IAnimationState {
-    data: IAnimationStateData;
-    tracks: ITrackEntry[];
-    listeners: IAnimationStateListener[];
-    timeScale: number;
-
-    update(dt: number): void;
-    apply(skeleton: ISkeleton): boolean;
-
-    setAnimation (trackIndex: number, animationName: string, loop: boolean): ITrackEntry;
-    addAnimation (trackIndex: number, animationName: string, loop: boolean, delay: number): ITrackEntry;
-    addEmptyAnimation (trackIndex: number, mixDuration: number, delay: number): ITrackEntry;
-    setEmptyAnimation (trackIndex: number, mixDuration: number): ITrackEntry;
-    setEmptyAnimations (mixDuration: number): void;
-    hasAnimation(animationName: string): boolean;
-    addListener (listener: IAnimationStateListener): void;
-    removeListener (listener: IAnimationStateListener): void;
-    clearListeners (): void;
-    clearTracks (): void;
-    clearTrack (index: number): void;
-}
-
-/**
- * @public
- */
-export interface IAnimationStateData {
-    skeletonData: ISkeletonData;
-    animationToMixTime: Map<number>;
-    defaultMix: number;
-    setMix (fromName: string, toName: string, duration: number): void;
-    setMixWith (from: Animation, to: Animation, duration: number): void;
-    getMix (from: Animation, to: Animation): number;
-}
-
-/**
- * @public
- */
-export interface IEventData {
-    name: string;
-}
-
-/**
- * @public
- */
-export interface IEvent {
-    time: number;
-    data: IEventData;
-}
-
-/**
- * @public
- */
-export interface IAnimationStateListener {
-    start? (entry: ITrackEntry): void;
-    interrupt? (entry: ITrackEntry): void;
-    end? (entry: ITrackEntry): void;
-    dispose? (entry: ITrackEntry): void;
-    complete? (entry: ITrackEntry): void;
-    event? (entry: ITrackEntry, event: IEvent): void;
+    findEvent (eventDataName: string): EventData | null;
+    findAnimation (animationName: string): Animation | null;
+    findIkConstraint (constraintName: string): IkConstraintData | null;
+    findTransformConstraint (constraintName: string): TransformConstraintData | null;
+    findPathConstraint (constraintName: string): PathConstraintData | null;
 }
diff --git a/packages/base/src/index.ts b/packages/base/src/index.ts
index 5c6d195c..38259601 100644
--- a/packages/base/src/index.ts
+++ b/packages/base/src/index.ts
@@ -1,6 +1,8 @@
 /// <reference path="../global.d.ts" />
 export * from './core/AttachmentType';
 export * from './core/BinaryInput';
+export * from './core/IAnimation';
+export * from './core/IConstraint';
 export * from './core/ISkeleton';
 export * from './core/TextureAtlas';
 export * from './core/TextureRegion';
diff --git a/packages/runtime-3.7/src/core/Animation.ts b/packages/runtime-3.7/src/core/Animation.ts
index a88a9953..c6be1d9b 100644
--- a/packages/runtime-3.7/src/core/Animation.ts
+++ b/packages/runtime-3.7/src/core/Animation.ts
@@ -1,7 +1,7 @@
 import {Event} from './Event';
 import type {Skeleton} from "./Skeleton";
 import {Attachment, VertexAttachment} from "./attachments";
-import {ArrayLike, MathUtils, Utils} from '@pixi-spine/base';
+import {ArrayLike, MathUtils, Utils, MixBlend, MixDirection, IAnimation, ITimeline} from '@pixi-spine/base';
 import {Slot} from "./Slot";
 import {IkConstraint} from "./IkConstraint";
 import {TransformConstraint} from "./TransformConstraint";
@@ -10,7 +10,7 @@ import {PathConstraint} from "./PathConstraint";
 /**
  * @public
  */
-export class Animation {
+export class Animation implements IAnimation<Timeline> {
     name: string;
     timelines: Array<Timeline>;
     duration: number;
@@ -61,28 +61,11 @@ export class Animation {
 /**
  * @public
  */
-export interface Timeline {
+export interface Timeline extends ITimeline {
     apply (skeleton: Skeleton, lastTime: number, time: number, events: Array<Event>, alpha: number, blend: MixBlend, direction: MixDirection): void;
     getPropertyId (): number;
 }
 
-/**
- * @public
- */
-export enum MixBlend {
-    setup,
-    first,
-    replace,
-    add
-}
-
-/**
- * @public
- */
-export enum MixDirection {
-    in, out
-}
-
 /**
  * @public
  */
@@ -402,7 +385,7 @@ export class ScaleTimeline extends TranslateTimeline {
             }
         } else {
             let bx = 0, by = 0;
-            if (direction == MixDirection.out) {
+            if (direction == MixDirection.mixOut) {
                 switch (blend) {
                     case MixBlend.setup:
                         bx = bone.data.scaleX;
@@ -718,7 +701,7 @@ export class AttachmentTimeline implements Timeline {
 
     apply (skeleton: Skeleton, lastTime: number, time: number, events: Array<Event>, alpha: number, blend: MixBlend, direction: MixDirection) {
         let slot = skeleton.slots[this.slotIndex];
-        if (direction == MixDirection.out && blend == MixBlend.setup) {
+        if (direction == MixDirection.mixOut && blend == MixBlend.setup) {
             let attachmentName = slot.data.attachmentName;
             slot.setAttachment(attachmentName == null ? null : skeleton.getAttachment(this.slotIndex, attachmentName));
             return;
@@ -1035,7 +1018,7 @@ export class DrawOrderTimeline implements Timeline {
     apply (skeleton: Skeleton, lastTime: number, time: number, firedEvents: Array<Event>, alpha: number, blend: MixBlend, direction: MixDirection) {
         let drawOrder: Array<Slot> = skeleton.drawOrder;
         let slots: Array<Slot> = skeleton.slots;
-        if (direction == MixDirection.out && blend == MixBlend.setup) {
+        if (direction == MixDirection.mixOut && blend == MixBlend.setup) {
             Utils.arrayCopy(skeleton.slots, 0, skeleton.drawOrder, 0, skeleton.slots.length);
             return;
         }
@@ -1115,7 +1098,7 @@ export class IkConstraintTimeline extends CurveTimeline {
         if (time >= frames[frames.length - IkConstraintTimeline.ENTRIES]) { // Time is after last frame.
             if (blend == MixBlend.setup) {
                 constraint.mix = constraint.data.mix + (frames[frames.length + IkConstraintTimeline.PREV_MIX] - constraint.data.mix) * alpha;
-                if (direction == MixDirection.out) {
+                if (direction == MixDirection.mixOut) {
                     constraint.bendDirection = constraint.data.bendDirection;
                     constraint.compress = constraint.data.compress;
                     constraint.stretch = constraint.data.stretch;
@@ -1126,7 +1109,7 @@ export class IkConstraintTimeline extends CurveTimeline {
                 }
             } else {
                 constraint.mix += (frames[frames.length + IkConstraintTimeline.PREV_MIX] - constraint.mix) * alpha;
-                if (direction == MixDirection.in) {
+                if (direction == MixDirection.mixIn) {
                     constraint.bendDirection = frames[frames.length + IkConstraintTimeline.PREV_BEND_DIRECTION];
                     constraint.compress = frames[frames.length + IkConstraintTimeline.PREV_COMPRESS] != 0;
                     constraint.stretch = frames[frames.length + IkConstraintTimeline.PREV_STRETCH] != 0;
@@ -1144,7 +1127,7 @@ export class IkConstraintTimeline extends CurveTimeline {
 
         if (blend == MixBlend.setup) {
             constraint.mix = constraint.data.mix + (mix + (frames[frame + IkConstraintTimeline.MIX] - mix) * percent - constraint.data.mix) * alpha;
-            if (direction == MixDirection.out) {
+            if (direction == MixDirection.mixOut) {
                 constraint.bendDirection = constraint.data.bendDirection;
                 constraint.compress = constraint.data.compress;
                 constraint.stretch = constraint.data.stretch;
@@ -1155,7 +1138,7 @@ export class IkConstraintTimeline extends CurveTimeline {
             }
         } else {
             constraint.mix += (mix + (frames[frame + IkConstraintTimeline.MIX] - mix) * percent - constraint.mix) * alpha;
-            if (direction == MixDirection.in) {
+            if (direction == MixDirection.mixIn) {
                 constraint.bendDirection = frames[frame + IkConstraintTimeline.PREV_BEND_DIRECTION];
                 constraint.compress = frames[frame + IkConstraintTimeline.PREV_COMPRESS] != 0;
                 constraint.stretch = frames[frame + IkConstraintTimeline.PREV_STRETCH] != 0;
diff --git a/packages/runtime-3.7/src/core/AnimationState.ts b/packages/runtime-3.7/src/core/AnimationState.ts
index c079f0b0..1dc59695 100644
--- a/packages/runtime-3.7/src/core/AnimationState.ts
+++ b/packages/runtime-3.7/src/core/AnimationState.ts
@@ -3,6 +3,8 @@ import {
     IAnimationStateListener,
     ITrackEntry,
     MathUtils,
+    MixBlend,
+    MixDirection,
     Pool,
     IntSet,
     Utils
@@ -11,8 +13,6 @@ import {
     Animation,
     AttachmentTimeline,
     DrawOrderTimeline,
-    MixBlend,
-    MixDirection,
     RotateTimeline, Timeline
 } from './Animation';
 import {AnimationStateData} from "./AnimationStateData";
@@ -22,7 +22,7 @@ import type {Skeleton} from "./Skeleton";
 /**
  * @public
  */
-export class AnimationState implements IAnimationState {
+export class AnimationState implements IAnimationState<AnimationStateData> {
     static emptyAnimation = new Animation("<empty>", [], 0);
     static SUBSEQUENT = 0;
     static FIRST = 1;
@@ -158,7 +158,7 @@ export class AnimationState implements IAnimationState {
                     // to sometimes stop rendering when using color correction, as their RGBA values become NaN.
                     // (https://github.com/pixijs/pixi-spine/issues/302)
                     Utils.webkit602BugfixHelper(mix, blend);
-                    timelines[ii].apply(skeleton, animationLast, animationTime, events, mix, blend, MixDirection.in);
+                    timelines[ii].apply(skeleton, animationLast, animationTime, events, mix, blend, MixDirection.mixIn);
                 }
             } else {
                 let timelineMode = current.timelineMode;
@@ -175,7 +175,7 @@ export class AnimationState implements IAnimationState {
                     } else {
                         // This fixes the WebKit 602 specific issue described at http://esotericsoftware.com/forum/iOS-10-disappearing-graphics-10109
                         Utils.webkit602BugfixHelper(mix, blend);
-                        timeline.apply(skeleton, animationLast, animationTime, events, mix, timelineBlend, MixDirection.in);
+                        timeline.apply(skeleton, animationLast, animationTime, events, mix, timelineBlend, MixDirection.mixIn);
                     }
                 }
             }
@@ -211,7 +211,7 @@ export class AnimationState implements IAnimationState {
         let alphaHold = from.alpha * to.interruptAlpha, alphaMix = alphaHold * (1 - mix);
         if (blend == MixBlend.add) {
             for (let i = 0; i < timelineCount; i++)
-                timelines[i].apply(skeleton, animationLast, animationTime, events, alphaMix, blend, MixDirection.out);
+                timelines[i].apply(skeleton, animationLast, animationTime, events, alphaMix, blend, MixDirection.mixOut);
         } else {
             let timelineMode = from.timelineMode;
             let timelineHoldMix = from.timelineHoldMix;
@@ -223,7 +223,7 @@ export class AnimationState implements IAnimationState {
             from.totalAlpha = 0;
             for (let i = 0; i < timelineCount; i++) {
                 let timeline = timelines[i];
-                let direction = MixDirection.out;
+                let direction = MixDirection.mixOut;
                 let timelineBlend: MixBlend;
                 let alpha = 0;
                 switch (timelineMode[i]) {
@@ -255,9 +255,9 @@ export class AnimationState implements IAnimationState {
                     Utils.webkit602BugfixHelper(alpha, blend);
                     if (timelineBlend == MixBlend.setup) {
                         if (timeline instanceof AttachmentTimeline) {
-                            if (attachments) direction = MixDirection.out;
+                            if (attachments) direction = MixDirection.mixOut;
                         } else if (timeline instanceof DrawOrderTimeline) {
-                            if (drawOrder) direction = MixDirection.out;
+                            if (drawOrder) direction = MixDirection.mixOut;
                         }
                     }
                     timeline.apply(skeleton, animationLast, animationTime, events, alpha, timelineBlend, direction);
@@ -279,7 +279,7 @@ export class AnimationState implements IAnimationState {
         if (firstFrame) timelinesRotation[i] = 0;
 
         if (alpha == 1) {
-            timeline.apply(skeleton, 0, time, null, 1, blend, MixDirection.in);
+            timeline.apply(skeleton, 0, time, null, 1, blend, MixDirection.mixIn);
             return;
         }
 
diff --git a/packages/runtime-3.7/src/core/AnimationStateData.ts b/packages/runtime-3.7/src/core/AnimationStateData.ts
index 6b44bb73..1750d2e5 100644
--- a/packages/runtime-3.7/src/core/AnimationStateData.ts
+++ b/packages/runtime-3.7/src/core/AnimationStateData.ts
@@ -5,7 +5,7 @@ import type {Animation} from './Animation';
 /**
  * @public
  */
-export class AnimationStateData implements IAnimationStateData {
+export class AnimationStateData implements IAnimationStateData<SkeletonData, Animation> {
     skeletonData: SkeletonData;
     animationToMixTime: Map<number> = {};
     defaultMix = 0;
diff --git a/packages/runtime-3.7/src/core/Bone.ts b/packages/runtime-3.7/src/core/Bone.ts
index 628b5e16..a1f74eeb 100644
--- a/packages/runtime-3.7/src/core/Bone.ts
+++ b/packages/runtime-3.7/src/core/Bone.ts
@@ -1,8 +1,8 @@
 import {Matrix} from '@pixi/math';
 import {Updatable} from "./Updatable";
-import {BoneData, TransformMode} from "./BoneData";
+import {BoneData} from "./BoneData";
 import {Skeleton} from "./Skeleton";
-import {IBone, MathUtils, settings, Vector2} from "@pixi-spine/base";
+import {IBone, MathUtils, settings, TransformMode, Vector2} from "@pixi-spine/base";
 
 /**
  * @public
diff --git a/packages/runtime-3.7/src/core/BoneData.ts b/packages/runtime-3.7/src/core/BoneData.ts
index c483a95c..982f423d 100644
--- a/packages/runtime-3.7/src/core/BoneData.ts
+++ b/packages/runtime-3.7/src/core/BoneData.ts
@@ -1,3 +1,5 @@
+import { TransformMode } from "@pixi-spine/base";
+
 /**
  * @public
  */
@@ -23,10 +25,3 @@ export class BoneData {
         this.parent = parent;
     }
 }
-
-/**
- * @public
- */
-export enum TransformMode {
-    Normal, OnlyTranslation, NoRotationOrReflection, NoScale, NoScaleOrReflection
-}
diff --git a/packages/runtime-3.7/src/core/PathConstraint.ts b/packages/runtime-3.7/src/core/PathConstraint.ts
index f55cba1b..16fbf982 100644
--- a/packages/runtime-3.7/src/core/PathConstraint.ts
+++ b/packages/runtime-3.7/src/core/PathConstraint.ts
@@ -1,10 +1,10 @@
 import {PathAttachment} from "./attachments";
 import {Constraint} from "./Constraint";
-import {PathConstraintData, PositionMode, RotateMode, SpacingMode} from "./PathConstraintData";
+import {PathConstraintData, SpacingMode} from "./PathConstraintData";
 import {Bone} from "./Bone";
 import {Slot} from "./Slot";
 import {Skeleton} from "./Skeleton";
-import {MathUtils, Utils} from "@pixi-spine/base";
+import {MathUtils, PositionMode, RotateMode, Utils} from "@pixi-spine/base";
 
 /**
  * @public
diff --git a/packages/runtime-3.7/src/core/PathConstraintData.ts b/packages/runtime-3.7/src/core/PathConstraintData.ts
index f0998363..0f1ef4ae 100644
--- a/packages/runtime-3.7/src/core/PathConstraintData.ts
+++ b/packages/runtime-3.7/src/core/PathConstraintData.ts
@@ -1,10 +1,11 @@
 import type {SlotData} from "./SlotData";
 import type {BoneData} from "./BoneData";
+import { RotateMode, PositionMode, IPathConstraintData } from "@pixi-spine/base";
 
 /**
  * @public
  */
-export class PathConstraintData {
+export class PathConstraintData implements IPathConstraintData {
     name: string;
     order = 0;
     bones = new Array<BoneData>();
@@ -23,23 +24,9 @@ export class PathConstraintData {
     }
 }
 
-/**
- * @public
- */
-export enum PositionMode {
-    Fixed, Percent
-}
-
 /**
  * @public
  */
 export enum SpacingMode {
     Length, Fixed, Percent
 }
-
-/**
- * @public
- */
-export enum RotateMode {
-    Tangent, Chain, ChainScale
-}
diff --git a/packages/runtime-3.7/src/core/Skeleton.ts b/packages/runtime-3.7/src/core/Skeleton.ts
index 400cf478..f51435fb 100644
--- a/packages/runtime-3.7/src/core/Skeleton.ts
+++ b/packages/runtime-3.7/src/core/Skeleton.ts
@@ -12,7 +12,7 @@ import {Color, Utils, Vector2, ISkeleton} from "@pixi-spine/base";
 /**
  * @public
  */
-export class Skeleton implements ISkeleton<Bone, Slot> {
+export class Skeleton implements ISkeleton<SkeletonData, Bone, Slot, Skin> {
     data: SkeletonData;
     bones: Array<Bone>;
     slots: Array<Slot>;
diff --git a/packages/runtime-3.7/src/core/SkeletonData.ts b/packages/runtime-3.7/src/core/SkeletonData.ts
index 73dd2746..956c05f7 100644
--- a/packages/runtime-3.7/src/core/SkeletonData.ts
+++ b/packages/runtime-3.7/src/core/SkeletonData.ts
@@ -1,16 +1,17 @@
+import type {ISkeletonData} from "@pixi-spine/base";
 import type {Animation} from "./Animation";
 import {BoneData} from "./BoneData";
 import {SlotData} from "./SlotData";
 import {Skin} from "./Skin";
-import {IkConstraintData} from "./IkConstraintData";
 import {EventData} from "./EventData";
+import {IkConstraintData} from "./IkConstraintData";
 import {TransformConstraintData} from "./TransformConstraintData";
 import {PathConstraintData} from "./PathConstraintData";
 
 /**
  * @public
  */
-export class SkeletonData {
+export class SkeletonData implements ISkeletonData<BoneData, SlotData, Skin, Animation, EventData, IkConstraintData, TransformConstraintData, PathConstraintData> {
     name: string;
     bones = new Array<BoneData>(); // Ordered parents first.
     slots = new Array<SlotData>(); // Setup pose draw order.
diff --git a/packages/runtime-3.7/src/core/SkeletonJson.ts b/packages/runtime-3.7/src/core/SkeletonJson.ts
index 4f59ddd6..9e298d4e 100644
--- a/packages/runtime-3.7/src/core/SkeletonJson.ts
+++ b/packages/runtime-3.7/src/core/SkeletonJson.ts
@@ -3,10 +3,10 @@ import {Animation} from './Animation';
 import {Event} from './Event';
 import {SkeletonData} from './SkeletonData';
 import {SlotData} from './SlotData';
-import {BoneData, TransformMode} from './BoneData';
+import {BoneData} from './BoneData';
 import {IkConstraintData} from './IkConstraintData';
 import {TransformConstraintData} from './TransformConstraintData';
-import {PathConstraintData, PositionMode, RotateMode, SpacingMode} from './PathConstraintData';
+import {PathConstraintData, SpacingMode} from './PathConstraintData';
 import {Skin} from './Skin';
 import {EventData} from './EventData';
 import {
@@ -24,7 +24,7 @@ import {
     TranslateTimeline,
     TwoColorTimeline
 } from './Animation';
-import {ArrayLike, Color, Utils, settings} from '@pixi-spine/base';
+import {ArrayLike, Color, Utils, PositionMode, RotateMode, TransformMode, settings} from '@pixi-spine/base';
 import {BLEND_MODES} from '@pixi/constants';
 
 /**
diff --git a/packages/runtime-3.7/src/core/Skin.ts b/packages/runtime-3.7/src/core/Skin.ts
index e26ccc95..76f1dff2 100644
--- a/packages/runtime-3.7/src/core/Skin.ts
+++ b/packages/runtime-3.7/src/core/Skin.ts
@@ -1,12 +1,12 @@
 import {Attachment} from './attachments';
 import {Skeleton} from "./Skeleton";
 
-import type {Map} from '@pixi-spine/base';
+import type {Map, ISkin} from '@pixi-spine/base';
 
 /**
  * @public
  */
-export class Skin {
+export class Skin implements ISkin {
     name: string;
     attachments = new Array<Map<Attachment>>();
 
diff --git a/packages/runtime-3.8/src/core/Animation.ts b/packages/runtime-3.8/src/core/Animation.ts
index 3bc49c3a..cddda4cc 100644
--- a/packages/runtime-3.8/src/core/Animation.ts
+++ b/packages/runtime-3.8/src/core/Animation.ts
@@ -1,7 +1,7 @@
 import {Event} from './Event';
 import type {Skeleton} from "./Skeleton";
 import {Attachment, VertexAttachment} from "./attachments";
-import {ArrayLike, MathUtils, Utils} from '@pixi-spine/base';
+import {ArrayLike, MathUtils, Utils, MixBlend, MixDirection} from '@pixi-spine/base';
 import {Slot} from "./Slot";
 import {IkConstraint} from "./IkConstraint";
 import {TransformConstraint} from "./TransformConstraint";
@@ -104,48 +104,6 @@ export interface Timeline {
     getPropertyId (): number;
 }
 
-/** Controls how a timeline value is mixed with the setup pose value or current pose value when a timeline's `alpha`
- * < 1.
- *
- * See Timeline {@link Timeline#apply(Skeleton, float, float, Array, float, MixBlend, MixDirection)}. */
-/**
- * @public
- */
-export enum MixBlend {
-    /** Transitions from the setup value to the timeline value (the current value is not used). Before the first key, the setup
-     * value is set. */
-    setup,
-    /** Transitions from the current value to the timeline value. Before the first key, transitions from the current value to
-     * the setup value. Timelines which perform instant transitions, such as {@link DrawOrderTimeline} or
-     * {@link AttachmentTimeline}, use the setup value before the first key.
-     *
-     * `first` is intended for the first animations applied, not for animations layered on top of those. */
-    first,
-    /** Transitions from the current value to the timeline value. No change is made before the first key (the current value is
-     * kept until the first key).
-     *
-     * `replace` is intended for animations layered on top of others, not for the first animations applied. */
-    replace,
-    /** Transitions from the current value to the current value plus the timeline value. No change is made before the first key
-     * (the current value is kept until the first key).
-     *
-     * `add` is intended for animations layered on top of others, not for the first animations applied. Properties
-     * keyed by additive animations must be set manually or by another animation before applying the additive animations, else
-     * the property values will increase continually. */
-    add
-}
-
-/** Indicates whether a timeline's `alpha` is mixing out over time toward 0 (the setup or current pose value) or
- * mixing in toward 1 (the timeline's value).
- *
- * See Timeline {@link Timeline#apply(Skeleton, float, float, Array, float, MixBlend, MixDirection)}. */
-/**
- * @public
- */
-export enum MixDirection {
-    mixIn, mixOut
-}
-
 /**
  * @public
  */
diff --git a/packages/runtime-3.8/src/core/AnimationState.ts b/packages/runtime-3.8/src/core/AnimationState.ts
index cc3a003d..af2a518e 100644
--- a/packages/runtime-3.8/src/core/AnimationState.ts
+++ b/packages/runtime-3.8/src/core/AnimationState.ts
@@ -2,6 +2,8 @@ import {
     IAnimationState,
     IAnimationStateListener,
     ITrackEntry,
+    MixBlend,
+    MixDirection,
     MathUtils,
     Pool,
     IntSet,
@@ -12,8 +14,6 @@ import {
     AttachmentTimeline,
     DrawOrderTimeline,
     EventTimeline,
-    MixBlend,
-    MixDirection,
     RotateTimeline, Timeline
 } from './Animation';
 import {AnimationStateData} from "./AnimationStateData";
@@ -28,7 +28,7 @@ import type {Slot} from "./Slot";
 /**
  * @public
  */
-export class AnimationState implements IAnimationState {
+export class AnimationState implements IAnimationState<AnimationStateData> {
     static emptyAnimation = new Animation("<empty>", [], 0);
 
     /** 1. A previously applied timeline has set this property.
diff --git a/packages/runtime-3.8/src/core/AnimationStateData.ts b/packages/runtime-3.8/src/core/AnimationStateData.ts
index 6b44bb73..52ca5ab0 100644
--- a/packages/runtime-3.8/src/core/AnimationStateData.ts
+++ b/packages/runtime-3.8/src/core/AnimationStateData.ts
@@ -1,11 +1,11 @@
 import {SkeletonData} from "./SkeletonData";
-import {IAnimationStateData, Map} from '@pixi-spine/base';
-import type {Animation} from './Animation';
+import {IAnimation, IAnimationStateData, Map} from '@pixi-spine/base';
+import type { Animation } from "./Animation";
 
 /**
  * @public
  */
-export class AnimationStateData implements IAnimationStateData {
+export class AnimationStateData implements IAnimationStateData<SkeletonData, Animation> {
     skeletonData: SkeletonData;
     animationToMixTime: Map<number> = {};
     defaultMix = 0;
@@ -33,14 +33,14 @@ export class AnimationStateData implements IAnimationStateData {
         this.setMix(fromName, toName, duration);
     }
 
-    setMixWith(from: Animation, to: Animation, duration: number) {
+    setMixWith(from: IAnimation, to: IAnimation, duration: number) {
         if (from == null) throw new Error("from cannot be null.");
         if (to == null) throw new Error("to cannot be null.");
         let key = from.name + "." + to.name;
         this.animationToMixTime[key] = duration;
     }
 
-    getMix(from: Animation, to: Animation) {
+    getMix(from: IAnimation, to: IAnimation) {
         let key = from.name + "." + to.name;
         let value = this.animationToMixTime[key];
         return value === undefined ? this.defaultMix : value;
diff --git a/packages/runtime-3.8/src/core/Bone.ts b/packages/runtime-3.8/src/core/Bone.ts
index 838759c1..cf23f0e7 100644
--- a/packages/runtime-3.8/src/core/Bone.ts
+++ b/packages/runtime-3.8/src/core/Bone.ts
@@ -1,8 +1,8 @@
 import {Matrix} from '@pixi/math';
 import {Updatable} from "./Updatable";
-import {BoneData, TransformMode} from "./BoneData";
+import {BoneData} from "./BoneData";
 import {Skeleton} from "./Skeleton";
-import {IBone, MathUtils, settings, Vector2} from "@pixi-spine/base";
+import {IBone, MathUtils, settings, TransformMode, Vector2} from "@pixi-spine/base";
 
 /**
  * @public
diff --git a/packages/runtime-3.8/src/core/BoneData.ts b/packages/runtime-3.8/src/core/BoneData.ts
index cb71a0b1..abdc33a0 100644
--- a/packages/runtime-3.8/src/core/BoneData.ts
+++ b/packages/runtime-3.8/src/core/BoneData.ts
@@ -1,4 +1,4 @@
-import {Color} from '@pixi-spine/base';
+import {Color, TransformMode} from '@pixi-spine/base';
 
 /**
  * @public
@@ -28,10 +28,3 @@ export class BoneData {
         this.parent = parent;
     }
 }
-
-/**
- * @public
- */
-export enum TransformMode {
-    Normal, OnlyTranslation, NoRotationOrReflection, NoScale, NoScaleOrReflection
-}
diff --git a/packages/runtime-3.8/src/core/IkConstraint.ts b/packages/runtime-3.8/src/core/IkConstraint.ts
index 4c175d78..80c0eb20 100644
--- a/packages/runtime-3.8/src/core/IkConstraint.ts
+++ b/packages/runtime-3.8/src/core/IkConstraint.ts
@@ -2,13 +2,12 @@ import {Updatable} from "./Updatable";
 import {IkConstraintData} from "./IkConstraintData";
 import {Bone} from "./Bone";
 import {Skeleton} from "./Skeleton";
-import {TransformMode} from "./BoneData";
-import {MathUtils} from "@pixi-spine/base";
+import {IIkConstraint, MathUtils, TransformMode} from "@pixi-spine/base";
 
 /**
  * @public
  */
-export class IkConstraint implements Updatable {
+export class IkConstraint implements IIkConstraint, Updatable {
     data: IkConstraintData;
     bones: Array<Bone>;
     target: Bone;
diff --git a/packages/runtime-3.8/src/core/IkConstraintData.ts b/packages/runtime-3.8/src/core/IkConstraintData.ts
index 387442f4..258917f8 100644
--- a/packages/runtime-3.8/src/core/IkConstraintData.ts
+++ b/packages/runtime-3.8/src/core/IkConstraintData.ts
@@ -1,10 +1,11 @@
 import {ConstraintData} from "./Constraint";
 import {BoneData} from "./BoneData";
+import {IIkConstraintData} from "@pixi-spine/base";
 
 /**
  * @public
  */
-export class IkConstraintData extends ConstraintData {
+export class IkConstraintData extends ConstraintData implements IIkConstraintData {
     bones = new Array<BoneData>();
     target: BoneData;
     bendDirection = 1;
diff --git a/packages/runtime-3.8/src/core/PathConstraint.ts b/packages/runtime-3.8/src/core/PathConstraint.ts
index 6fbccf7d..945227e4 100644
--- a/packages/runtime-3.8/src/core/PathConstraint.ts
+++ b/packages/runtime-3.8/src/core/PathConstraint.ts
@@ -1,10 +1,10 @@
 import {PathAttachment} from "./attachments";
 import {Updatable} from "./Updatable";
-import {PathConstraintData, PositionMode, RotateMode, SpacingMode} from "./PathConstraintData";
+import {PathConstraintData, SpacingMode} from "./PathConstraintData";
 import {Bone} from "./Bone";
 import {Slot} from "./Slot";
 import {Skeleton} from "./Skeleton";
-import {MathUtils, Utils} from "@pixi-spine/base";
+import {MathUtils, PositionMode, RotateMode, Utils} from "@pixi-spine/base";
 /**
  * @public
  */
diff --git a/packages/runtime-3.8/src/core/PathConstraintData.ts b/packages/runtime-3.8/src/core/PathConstraintData.ts
index 27025629..6de037df 100644
--- a/packages/runtime-3.8/src/core/PathConstraintData.ts
+++ b/packages/runtime-3.8/src/core/PathConstraintData.ts
@@ -1,6 +1,7 @@
 import {ConstraintData} from "./Constraint";
 import type {SlotData} from "./SlotData";
 import type {BoneData} from "./BoneData";
+import { RotateMode, PositionMode } from "@pixi-spine/base";
 
 /**
  * @public
@@ -18,21 +19,9 @@ export class PathConstraintData extends ConstraintData {
         super(name, 0, false);
     }
 }
-/**
- * @public
- */
-export enum PositionMode {
-    Fixed, Percent
-}
 /**
  * @public
  */
 export enum SpacingMode {
     Length, Fixed, Percent
 }
-/**
- * @public
- */
-export enum RotateMode {
-    Tangent, Chain, ChainScale
-}
diff --git a/packages/runtime-3.8/src/core/Skeleton.ts b/packages/runtime-3.8/src/core/Skeleton.ts
index 91935393..2bfe0806 100644
--- a/packages/runtime-3.8/src/core/Skeleton.ts
+++ b/packages/runtime-3.8/src/core/Skeleton.ts
@@ -12,7 +12,7 @@ import {Color, Utils, Vector2, ISkeleton} from "@pixi-spine/base";
 /**
  * @public
  */
-export class Skeleton implements ISkeleton<Bone, Slot> {
+export class Skeleton implements ISkeleton<SkeletonData, Bone, Slot, Skin> {
     data: SkeletonData;
     bones: Array<Bone>;
     slots: Array<Slot>;
diff --git a/packages/runtime-3.8/src/core/SkeletonBinary.ts b/packages/runtime-3.8/src/core/SkeletonBinary.ts
index 415dbb91..ff36923d 100644
--- a/packages/runtime-3.8/src/core/SkeletonBinary.ts
+++ b/packages/runtime-3.8/src/core/SkeletonBinary.ts
@@ -3,10 +3,10 @@ import {Animation} from './Animation';
 import {Event} from './Event';
 import {SkeletonData} from './SkeletonData';
 import {SlotData} from './SlotData';
-import {BoneData, TransformMode} from './BoneData';
+import {BoneData} from './BoneData';
 import {IkConstraintData} from './IkConstraintData';
 import {TransformConstraintData} from './TransformConstraintData';
-import {PathConstraintData, PositionMode, RotateMode, SpacingMode} from './PathConstraintData';
+import {PathConstraintData, SpacingMode} from './PathConstraintData';
 import {Skin} from './Skin';
 import {EventData} from './EventData';
 import {
@@ -24,7 +24,7 @@ import {
     TranslateTimeline,
     TwoColorTimeline
 } from './Animation';
-import {AttachmentType, BinaryInput, Color, Utils} from '@pixi-spine/base';
+import {AttachmentType, BinaryInput, Color, PositionMode, RotateMode, TransformMode, Utils} from '@pixi-spine/base';
 import {BLEND_MODES} from '@pixi/constants';
 
 /**
diff --git a/packages/runtime-3.8/src/core/SkeletonData.ts b/packages/runtime-3.8/src/core/SkeletonData.ts
index 10cbfcd0..308eba74 100644
--- a/packages/runtime-3.8/src/core/SkeletonData.ts
+++ b/packages/runtime-3.8/src/core/SkeletonData.ts
@@ -1,16 +1,17 @@
+import type {ISkeletonData} from '@pixi-spine/base';
 import type {Animation} from "./Animation";
 import {BoneData} from "./BoneData";
 import {SlotData} from "./SlotData";
 import {Skin} from "./Skin";
-import {IkConstraintData} from "./IkConstraintData";
 import {EventData} from "./EventData";
+import {IkConstraintData} from "./IkConstraintData";
 import {TransformConstraintData} from "./TransformConstraintData";
 import {PathConstraintData} from "./PathConstraintData";
 
 /**
  * @public
  */
-export class SkeletonData {
+export class SkeletonData implements ISkeletonData<BoneData, SlotData, Skin, Animation, EventData, IkConstraintData, TransformConstraintData, PathConstraintData> {
     name: string;
     bones = new Array<BoneData>(); // Ordered parents first.
     slots = new Array<SlotData>(); // Setup pose draw order.
diff --git a/packages/runtime-3.8/src/core/SkeletonJson.ts b/packages/runtime-3.8/src/core/SkeletonJson.ts
index 83fcb8f8..1145d88c 100644
--- a/packages/runtime-3.8/src/core/SkeletonJson.ts
+++ b/packages/runtime-3.8/src/core/SkeletonJson.ts
@@ -3,10 +3,10 @@ import {Animation} from './Animation';
 import {Event} from './Event';
 import {SkeletonData} from './SkeletonData';
 import {SlotData} from './SlotData';
-import {BoneData, TransformMode} from './BoneData';
+import {BoneData} from './BoneData';
 import {IkConstraintData} from './IkConstraintData';
 import {TransformConstraintData} from './TransformConstraintData';
-import {PathConstraintData, PositionMode, RotateMode, SpacingMode} from './PathConstraintData';
+import {PathConstraintData, SpacingMode} from './PathConstraintData';
 import {Skin} from './Skin';
 import {EventData} from './EventData';
 import {
@@ -24,7 +24,7 @@ import {
     TranslateTimeline,
     TwoColorTimeline
 } from './Animation';
-import {ArrayLike, Color, Utils, settings} from '@pixi-spine/base';
+import {ArrayLike, Color, PositionMode, RotateMode, TransformMode, Utils, settings} from '@pixi-spine/base';
 import {BLEND_MODES} from '@pixi/constants';
 
 /**
diff --git a/packages/runtime-3.8/src/core/Skin.ts b/packages/runtime-3.8/src/core/Skin.ts
index feb3fe45..a7be47d5 100644
--- a/packages/runtime-3.8/src/core/Skin.ts
+++ b/packages/runtime-3.8/src/core/Skin.ts
@@ -3,7 +3,7 @@ import {BoneData} from "./BoneData";
 import {ConstraintData} from "./Constraint";
 import {Skeleton} from "./Skeleton";
 
-import type {Map} from '@pixi-spine/base';
+import type {Map, ISkin} from '@pixi-spine/base';
 
 /**
  * @public
@@ -15,7 +15,7 @@ export class SkinEntry {
 /**
  * @public
  */
-export class Skin {
+export class Skin implements ISkin {
     name: string;
     attachments = new Array<Map<Attachment>>();
     bones = Array<BoneData>();
diff --git a/packages/runtime-4.0/src/core/Animation.ts b/packages/runtime-4.0/src/core/Animation.ts
index 174ca2e8..aab495cc 100644
--- a/packages/runtime-4.0/src/core/Animation.ts
+++ b/packages/runtime-4.0/src/core/Animation.ts
@@ -1,7 +1,7 @@
 import {Event} from './Event';
 import type {Skeleton} from "./Skeleton";
 import {Attachment, VertexAttachment} from "./attachments";
-import {ArrayLike, MathUtils, StringSet, Utils} from '@pixi-spine/base';
+import {ArrayLike, IAnimation, ITimeline, MathUtils, MixBlend, StringSet, Utils, MixDirection} from '@pixi-spine/base';
 import {Slot} from "./Slot";
 import {IkConstraint} from "./IkConstraint";
 import {TransformConstraint} from "./TransformConstraint";
@@ -10,7 +10,7 @@ import {PathConstraint} from "./PathConstraint";
  * A simple container for a list of timelines and a name.
  * @public
  * */
-export class Animation {
+export class Animation implements IAnimation<Timeline> {
     /** The animation's name, which is unique across all animations in the skeleton. */
     name: string;
     timelines: Array<Timeline>;
@@ -59,46 +59,6 @@ export class Animation {
     }
 }
 
-/** Controls how a timeline value is mixed with the setup pose value or current pose value when a timeline's `alpha`
- * < 1.
- *
- * See Timeline {@link Timeline#apply(Skeleton, float, float, Array, float, MixBlend, MixDirection)}.
- * @public
- * */
-export enum MixBlend {
-    /** Transitions from the setup value to the timeline value (the current value is not used). Before the first key, the setup
-     * value is set. */
-    setup,
-    /** Transitions from the current value to the timeline value. Before the first key, transitions from the current value to
-     * the setup value. Timelines which perform instant transitions, such as {@link DrawOrderTimeline} or
-     * {@link AttachmentTimeline}, use the setup value before the first key.
-     *
-     * `first` is intended for the first animations applied, not for animations layered on top of those. */
-    first,
-    /** Transitions from the current value to the timeline value. No change is made before the first key (the current value is
-     * kept until the first key).
-     *
-     * `replace` is intended for animations layered on top of others, not for the first animations applied. */
-    replace,
-    /** Transitions from the current value to the current value plus the timeline value. No change is made before the first key
-     * (the current value is kept until the first key).
-     *
-     * `add` is intended for animations layered on top of others, not for the first animations applied. Properties
-     * keyed by additive animations must be set manually or by another animation before applying the additive animations, else
-     * the property values will increase continually. */
-    add
-}
-
-/** Indicates whether a timeline's `alpha` is mixing out over time toward 0 (the setup or current pose value) or
- * mixing in toward 1 (the timeline's value).
- *
- * See Timeline {@link Timeline#apply(Skeleton, float, float, Array, float, MixBlend, MixDirection)}.
- * @public
- * */
-export enum MixDirection {
-    mixIn, mixOut
-}
-
 const Property = {
     rotate: 0,
     x: 1,
@@ -129,7 +89,7 @@ const Property = {
 /** The interface for all timelines.
  * @public
  * */
-export abstract class Timeline {
+export abstract class Timeline implements ITimeline {
     propertyIds: string[];
     frames: ArrayLike<number>;
 
diff --git a/packages/runtime-4.0/src/core/AnimationState.ts b/packages/runtime-4.0/src/core/AnimationState.ts
index 7abb4d21..a0ca1293 100644
--- a/packages/runtime-4.0/src/core/AnimationState.ts
+++ b/packages/runtime-4.0/src/core/AnimationState.ts
@@ -3,6 +3,8 @@ import {
     IAnimationStateListener,
     ITrackEntry,
     MathUtils,
+    MixBlend,
+    MixDirection,
     Pool,
     StringSet,
     Utils
@@ -12,8 +14,6 @@ import {
     AttachmentTimeline,
     DrawOrderTimeline,
     EventTimeline,
-    MixBlend,
-    MixDirection,
     RotateTimeline, Timeline
 } from './Animation';
 import {AnimationStateData} from "./AnimationStateData";
@@ -27,7 +27,7 @@ import type {Slot} from "./Slot";
  * See [Applying Animations](http://esotericsoftware.com/spine-applying-animations/) in the Spine Runtimes Guide.
  * @public
  * */
-export class AnimationState implements IAnimationState {
+export class AnimationState implements IAnimationState<AnimationStateData> {
     private static emptyAnimation (): Animation {
         if (!_emptyAnimation) _emptyAnimation = new Animation("<empty>", [], 0);
         return _emptyAnimation;
diff --git a/packages/runtime-4.0/src/core/AnimationStateData.ts b/packages/runtime-4.0/src/core/AnimationStateData.ts
index 9d3e75c2..6a5fd25d 100644
--- a/packages/runtime-4.0/src/core/AnimationStateData.ts
+++ b/packages/runtime-4.0/src/core/AnimationStateData.ts
@@ -5,7 +5,7 @@ import type {Animation} from './Animation';
 /** Stores mix (crossfade) durations to be applied when {@link AnimationState} animations are changed.
  * @public
  * */
-export class AnimationStateData implements IAnimationStateData {
+export class AnimationStateData implements IAnimationStateData<SkeletonData, Animation> {
     /** The SkeletonData to look up animations when they are specified by name. */
     skeletonData: SkeletonData;
 
diff --git a/packages/runtime-4.0/src/core/Bone.ts b/packages/runtime-4.0/src/core/Bone.ts
index 371595cd..4c8d2fee 100644
--- a/packages/runtime-4.0/src/core/Bone.ts
+++ b/packages/runtime-4.0/src/core/Bone.ts
@@ -1,8 +1,8 @@
 import {Matrix} from '@pixi/math';
 import {Updatable} from "./Updatable";
-import {BoneData, TransformMode} from "./BoneData";
+import {BoneData} from "./BoneData";
 import {Skeleton} from "./Skeleton";
-import {IBone, MathUtils, settings, Vector2} from "@pixi-spine/base";
+import {IBone, MathUtils, settings, TransformMode, Vector2} from "@pixi-spine/base";
 
 /** Stores a bone's current pose.
  *
diff --git a/packages/runtime-4.0/src/core/BoneData.ts b/packages/runtime-4.0/src/core/BoneData.ts
index f42f155b..eaf9fbd3 100644
--- a/packages/runtime-4.0/src/core/BoneData.ts
+++ b/packages/runtime-4.0/src/core/BoneData.ts
@@ -1,4 +1,4 @@
-import {Color} from '@pixi-spine/base';
+import {Color, TransformMode} from '@pixi-spine/base';
 
 /** Stores the setup pose for a {@link Bone}.
  * @public
@@ -57,10 +57,3 @@ export class BoneData {
         this.parent = parent;
     }
 }
-
-/** Determines how a bone inherits world transforms from parent bones.
- * @public
- * */
-export enum TransformMode {
-    Normal, OnlyTranslation, NoRotationOrReflection, NoScale, NoScaleOrReflection
-}
diff --git a/packages/runtime-4.0/src/core/IkConstraint.ts b/packages/runtime-4.0/src/core/IkConstraint.ts
index c5613dd0..58238b03 100644
--- a/packages/runtime-4.0/src/core/IkConstraint.ts
+++ b/packages/runtime-4.0/src/core/IkConstraint.ts
@@ -2,8 +2,7 @@ import {Updatable} from "./Updatable";
 import {IkConstraintData} from "./IkConstraintData";
 import {Bone} from "./Bone";
 import {Skeleton} from "./Skeleton";
-import {TransformMode} from "./BoneData";
-import {MathUtils} from "@pixi-spine/base";
+import {MathUtils, TransformMode} from "@pixi-spine/base";
 
 /** Stores the current pose for an IK constraint. An IK constraint adjusts the rotation of 1 or 2 constrained bones so the tip of
  * the last bone is as close to the target bone as possible.
diff --git a/packages/runtime-4.0/src/core/PathConstraint.ts b/packages/runtime-4.0/src/core/PathConstraint.ts
index 86e72789..551b5a6d 100644
--- a/packages/runtime-4.0/src/core/PathConstraint.ts
+++ b/packages/runtime-4.0/src/core/PathConstraint.ts
@@ -1,10 +1,10 @@
 import {PathAttachment} from "./attachments";
 import {Updatable} from "./Updatable";
-import {PathConstraintData, PositionMode, RotateMode, SpacingMode} from "./PathConstraintData";
+import {PathConstraintData, SpacingMode} from "./PathConstraintData";
 import {Bone} from "./Bone";
 import {Slot} from "./Slot";
 import {Skeleton} from "./Skeleton";
-import {MathUtils, Utils} from "@pixi-spine/base";
+import {MathUtils, PositionMode, RotateMode, Utils} from "@pixi-spine/base";
 /** Stores the current pose for a path constraint. A path constraint adjusts the rotation, translation, and scale of the
  * constrained bones so they follow a {@link PathAttachment}.
  *
diff --git a/packages/runtime-4.0/src/core/PathConstraintData.ts b/packages/runtime-4.0/src/core/PathConstraintData.ts
index 26d6d80d..00e282ee 100644
--- a/packages/runtime-4.0/src/core/PathConstraintData.ts
+++ b/packages/runtime-4.0/src/core/PathConstraintData.ts
@@ -1,6 +1,7 @@
 import {ConstraintData} from "./ConstraintData";
 import type {SlotData} from "./SlotData";
 import type {BoneData} from "./BoneData";
+import { PositionMode, RotateMode } from "@pixi-spine/base";
 
 /** Stores the setup pose for a {@link PathConstraint}.
  *
@@ -42,15 +43,6 @@ export class PathConstraintData extends ConstraintData {
     }
 }
 
-/** Controls how the first bone is positioned along the path.
- *
- * See [Position mode](http://esotericsoftware.com/spine-path-constraints#Position-mode) in the Spine User Guide.
- * @public
- * */
-export enum PositionMode {
-    Fixed, Percent
-}
-
 /** Controls how bones after the first bone are positioned along the path.
  *
  * [Spacing mode](http://esotericsoftware.com/spine-path-constraints#Spacing-mode) in the Spine User Guide.
@@ -59,12 +51,3 @@ export enum PositionMode {
 export enum SpacingMode {
     Length, Fixed, Percent, Proportional
 }
-
-/** Controls how bones are rotated, translated, and scaled to match the path.
- *
- * [Rotate mode](http://esotericsoftware.com/spine-path-constraints#Rotate-mod) in the Spine User Guide.
- * @public
- * */
-export enum RotateMode {
-    Tangent, Chain, ChainScale
-}
diff --git a/packages/runtime-4.0/src/core/Skeleton.ts b/packages/runtime-4.0/src/core/Skeleton.ts
index f5640c92..a1d2de06 100644
--- a/packages/runtime-4.0/src/core/Skeleton.ts
+++ b/packages/runtime-4.0/src/core/Skeleton.ts
@@ -14,7 +14,7 @@ import {Color, MathUtils, settings, Utils, Vector2, ISkeleton} from "@pixi-spine
  * See [Instance objects](http://esotericsoftware.com/spine-runtime-architecture#Instance-objects) in the Spine Runtimes Guide.
  * @public
  * */
-export class Skeleton implements ISkeleton<Bone, Slot> {
+export class Skeleton implements ISkeleton<SkeletonData, Bone, Slot, Skin> {
     /** The skeleton's setup pose data. */
     data: SkeletonData;
 
diff --git a/packages/runtime-4.0/src/core/SkeletonBinary.ts b/packages/runtime-4.0/src/core/SkeletonBinary.ts
index 0369b9e1..7f5095d3 100644
--- a/packages/runtime-4.0/src/core/SkeletonBinary.ts
+++ b/packages/runtime-4.0/src/core/SkeletonBinary.ts
@@ -19,10 +19,10 @@ import {SlotData} from './SlotData';
 import {BoneData} from './BoneData';
 import {IkConstraintData} from './IkConstraintData';
 import {TransformConstraintData} from './TransformConstraintData';
-import {PathConstraintData, PositionMode, SpacingMode} from './PathConstraintData';
+import {PathConstraintData, SpacingMode} from './PathConstraintData';
 import {Skin} from './Skin';
 import {EventData} from './EventData';
-import {AttachmentType, BinaryInput, Color, Utils} from '@pixi-spine/base';
+import {AttachmentType, BinaryInput, Color, PositionMode, Utils} from '@pixi-spine/base';
 import {BLEND_MODES} from '@pixi/constants';
 
 /** Loads skeleton data in the Spine binary format.
diff --git a/packages/runtime-4.0/src/core/SkeletonData.ts b/packages/runtime-4.0/src/core/SkeletonData.ts
index d3a3b4e5..7fa55cf6 100644
--- a/packages/runtime-4.0/src/core/SkeletonData.ts
+++ b/packages/runtime-4.0/src/core/SkeletonData.ts
@@ -1,9 +1,10 @@
+import type {ISkeletonData} from "@pixi-spine/base";
 import type {Animation} from "./Animation";
 import {BoneData} from "./BoneData";
 import {SlotData} from "./SlotData";
 import {Skin} from "./Skin";
-import {IkConstraintData} from "./IkConstraintData";
 import {EventData} from "./EventData";
+import {IkConstraintData} from "./IkConstraintData";
 import {TransformConstraintData} from "./TransformConstraintData";
 import {PathConstraintData} from "./PathConstraintData";
 
@@ -13,7 +14,7 @@ import {PathConstraintData} from "./PathConstraintData";
  * Guide.
  * @public
  * */
-export class SkeletonData {
+export class SkeletonData implements ISkeletonData<BoneData, SlotData, Skin, Animation, EventData, IkConstraintData, TransformConstraintData, PathConstraintData> {
 
     /** The skeleton's name, which by default is the name of the skeleton data file, if possible. May be null. */
     name: string;
diff --git a/packages/runtime-4.0/src/core/SkeletonJson.ts b/packages/runtime-4.0/src/core/SkeletonJson.ts
index 3bdcc8a0..2f9d2979 100644
--- a/packages/runtime-4.0/src/core/SkeletonJson.ts
+++ b/packages/runtime-4.0/src/core/SkeletonJson.ts
@@ -16,13 +16,13 @@ import {
 import {Event} from './Event';
 import {SkeletonData} from './SkeletonData';
 import {SlotData} from './SlotData';
-import {BoneData, TransformMode} from './BoneData';
+import {BoneData} from './BoneData';
 import {IkConstraintData} from './IkConstraintData';
 import {TransformConstraintData} from './TransformConstraintData';
-import {PathConstraintData, PositionMode, RotateMode, SpacingMode} from './PathConstraintData';
+import {PathConstraintData, SpacingMode} from './PathConstraintData';
 import {Skin} from './Skin';
 import {EventData} from './EventData';
-import {ArrayLike, Color, Utils, settings} from '@pixi-spine/base';
+import {ArrayLike, Color, PositionMode, RotateMode, TransformMode, Utils, settings} from '@pixi-spine/base';
 import {BLEND_MODES} from '@pixi/constants';
 
 /** Loads skeleton data in the Spine JSON format.
diff --git a/packages/runtime-4.0/src/core/Skin.ts b/packages/runtime-4.0/src/core/Skin.ts
index 8fbd921c..2a2f797b 100644
--- a/packages/runtime-4.0/src/core/Skin.ts
+++ b/packages/runtime-4.0/src/core/Skin.ts
@@ -3,7 +3,7 @@ import {BoneData} from "./BoneData";
 import {ConstraintData} from "./ConstraintData";
 import {Skeleton} from "./Skeleton";
 
-import type {Map} from '@pixi-spine/base';
+import type {Map, ISkin} from '@pixi-spine/base';
 
 /** Stores an entry in the skin consisting of the slot index, name, and attachment
  * @public
@@ -18,7 +18,7 @@ export class SkinEntry {
  * [Runtime skins](http://esotericsoftware.com/spine-runtime-skins) in the Spine Runtimes Guide.
  * @public
  * */
-export class Skin {
+export class Skin implements ISkin {
     /** The skin's name, which is unique across all skins in the skeleton. */
     name: string;