diff --git a/packages/webamp/demo/js/Webamp.ts b/packages/webamp/demo/js/Webamp.ts
index 87bfbd5d..d26adde1 100644
--- a/packages/webamp/demo/js/Webamp.ts
+++ b/packages/webamp/demo/js/Webamp.ts
@@ -14,6 +14,7 @@ export {
   ButterchurnOptions,
   Track,
   AppState,
+  PartialState,
   URLTrack,
   FilePicker,
   Action,
diff --git a/packages/webamp/demo/js/config.ts b/packages/webamp/demo/js/config.ts
index 10293387..9bdaaa9f 100644
--- a/packages/webamp/demo/js/config.ts
+++ b/packages/webamp/demo/js/config.ts
@@ -1,14 +1,13 @@
-import { Track, AppState, URLTrack } from "./Webamp";
+import { Track, URLTrack, PartialState } from "./Webamp";
 // @ts-ignore
 import llamaAudio from "../mp3/llama-2.91.mp3";
-import { DeepPartial } from "redux";
 
 interface Config {
   initialTracks?: Track[];
   audioUrl?: string;
   skinUrl?: string;
   disableMarquee?: boolean;
-  initialState?: DeepPartial<AppState>;
+  initialState?: PartialState;
 }
 
 const { hash } = window.location;
diff --git a/packages/webamp/demo/js/screenshotInitialState.ts b/packages/webamp/demo/js/screenshotInitialState.ts
index 520756da..6080be51 100644
--- a/packages/webamp/demo/js/screenshotInitialState.ts
+++ b/packages/webamp/demo/js/screenshotInitialState.ts
@@ -1,5 +1,4 @@
-import { DeepPartial } from "redux";
-import { AppState } from "./Webamp";
+import { PartialState } from "./Webamp";
 
 const defaultTracksState = {
   "0": {
@@ -44,7 +43,7 @@ const defaultTracksState = {
   },
 };
 
-const initialState: DeepPartial<AppState> = {
+const initialState: PartialState = {
   equalizer: {
     sliders: {
       "60": 52,
diff --git a/packages/webamp/js/store.ts b/packages/webamp/js/store.ts
index c013db24..c3eaed98 100644
--- a/packages/webamp/js/store.ts
+++ b/packages/webamp/js/store.ts
@@ -1,4 +1,4 @@
-import { createStore, applyMiddleware, DeepPartial } from "redux";
+import { createStore, applyMiddleware } from "redux";
 import thunk from "redux-thunk";
 import { composeWithDevTools } from "redux-devtools-extension";
 import reducer from "./reducers";
@@ -7,7 +7,7 @@ import { merge } from "./utils";
 import { UPDATE_TIME_ELAPSED, STEP_MARQUEE } from "./actionTypes";
 import Media from "./media";
 import Emitter from "./emitter";
-import { Extras, Dispatch, Action, AppState, Middleware } from "./types";
+import { Extras, Dispatch, Action, Middleware, PartialState } from "./types";
 
 // TODO: Move to demo
 const compose = composeWithDevTools({
@@ -18,7 +18,7 @@ export default function (
   media: Media,
   actionEmitter: Emitter,
   customMiddlewares: Middleware[] = [],
-  stateOverrides: DeepPartial<AppState> | undefined,
+  stateOverrides: PartialState | undefined,
   extras: Extras
 ) {
   let initialState;
diff --git a/packages/webamp/js/types.ts b/packages/webamp/js/types.ts
index 2199d62f..bbdf9c38 100644
--- a/packages/webamp/js/types.ts
+++ b/packages/webamp/js/types.ts
@@ -666,6 +666,8 @@ export interface AppState {
   milkdrop: MilkdropState;
 }
 
+export type PartialState = any;
+
 /**
  * Type definition of the music-metadata-browser module.
  * Ref: https://github.com/Borewit/music-metadata-browser/blob/master/src/index.ts
@@ -732,7 +734,6 @@ export interface Store extends ReduxStore {
   subscribe(cb: () => void): () => void;
   dispatch: Dispatch;
   getState: GetState;
-  replaceReducer(reducer: Reducer): void;
 }
 
 export interface MiddlewareStore {
diff --git a/packages/webamp/js/webampLazy.tsx b/packages/webamp/js/webampLazy.tsx
index c4320b50..9d73b86c 100644
--- a/packages/webamp/js/webampLazy.tsx
+++ b/packages/webamp/js/webampLazy.tsx
@@ -10,6 +10,7 @@ import {
   Middleware,
   WindowPosition,
   ButterchurnOptions,
+  PartialState,
 } from "./types";
 import getStore from "./store";
 import App from "./components/App";
@@ -37,7 +38,6 @@ import Emitter from "./emitter";
 
 import { SerializedStateV1 } from "./serializedStates/v1Types";
 import Disposable from "./Disposable";
-import { DeepPartial } from "redux";
 
 export interface Options {
   /**
@@ -123,7 +123,7 @@ export interface PrivateOptions {
   avaliableSkins?: { url: string; name: string }[]; // Old misspelled name
   requireJSZip(): Promise<any>; // TODO: Type JSZip
   requireMusicMetadata(): Promise<any>; // TODO: Type musicmetadata
-  __initialState?: DeepPartial<AppState>;
+  __initialState?: PartialState;
   __customMiddlewares?: Middleware[];
   __initialWindowLayout?: WindowLayout;
   __butterchurnOptions?: ButterchurnOptions;
diff --git a/packages/webamp/package.json b/packages/webamp/package.json
index 1004e473..886059d7 100644
--- a/packages/webamp/package.json
+++ b/packages/webamp/package.json
@@ -69,7 +69,7 @@
     "@types/css-font-loading-module": "^0.0.2",
     "@types/fscreen": "^1.0.1",
     "@types/invariant": "^2.2.29",
-    "@types/jest": "^23.3.2",
+    "@types/jest": "^27.0.3",
     "@types/jszip": "^3.1.5",
     "@types/lodash": "^4.14.116",
     "@types/lodash-es": "^4.17.1",
diff --git a/packages/webamp/tsconfig.json b/packages/webamp/tsconfig.json
index f02dc7e6..ef5f7ceb 100644
--- a/packages/webamp/tsconfig.json
+++ b/packages/webamp/tsconfig.json
@@ -11,7 +11,7 @@
     "jsx": "preserve",
     "noEmit": true,
     "pretty": true,
-    "types": ["react/experimental", "react-dom/experimental"]
+    "types": ["react/experimental", "react-dom/experimental", "jest"]
   },
   "include": ["**/*.ts", "**/*.tsx"],
   "exclude": ["node_modules", "demo/built"]
diff --git a/yarn.lock b/yarn.lock
index 8b3f4b6b..880347ff 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3168,6 +3168,14 @@
     jest-diff "^26.0.0"
     pretty-format "^26.0.0"
 
+"@types/jest@^27.0.3":
+  version "27.0.3"
+  resolved "https://registry.yarnpkg.com/@types/jest/-/jest-27.0.3.tgz#0cf9dfe9009e467f70a342f0f94ead19842a783a"
+  integrity sha512-cmmwv9t7gBYt7hNKH5Spu7Kuu/DotGa+Ff+JGRKZ4db5eh8PnKS4LuebJ3YLUoyOyIHraTGyULn23YtEAm0VSg==
+  dependencies:
+    jest-diff "^27.0.0"
+    pretty-format "^27.0.0"
+
 "@types/json-schema@*", "@types/json-schema@^7.0.7":
   version "7.0.8"
   resolved "https://registry.yarnpkg.com/@types/json-schema/-/json-schema-7.0.8.tgz#edf1bf1dbf4e04413ca8e5b17b3b7d7d54b59818"
@@ -6239,6 +6247,11 @@ diff-sequences@^26.6.2:
   resolved "https://registry.yarnpkg.com/diff-sequences/-/diff-sequences-26.6.2.tgz#48ba99157de1923412eed41db6b6d4aa9ca7c0b1"
   integrity sha512-Mv/TDa3nZ9sbc5soK+OoA74BsS3mL37yixCvUAQkiuA4Wz6YtwP/K47n2rv2ovzHZvoiQeA5FTQOschKkEwB0Q==
 
+diff-sequences@^27.0.6:
+  version "27.0.6"
+  resolved "https://registry.yarnpkg.com/diff-sequences/-/diff-sequences-27.0.6.tgz#3305cb2e55a033924054695cc66019fd7f8e5723"
+  integrity sha512-ag6wfpBFyNXZ0p8pcuIDS//D8H062ZQJ3fzYxjpmeKjnz8W4pekL3AI8VohmyZmsWW2PWaHgjsmqR6L13101VQ==
+
 diff@^4.0.1:
   version "4.0.2"
   resolved "https://registry.yarnpkg.com/diff/-/diff-4.0.2.tgz#60f3aecb89d5fae520c11aa19efc2bb982aade7d"
@@ -9615,6 +9628,16 @@ jest-diff@^26.1.0:
     jest-get-type "^26.0.0"
     pretty-format "^26.1.0"
 
+jest-diff@^27.0.0:
+  version "27.3.1"
+  resolved "https://registry.yarnpkg.com/jest-diff/-/jest-diff-27.3.1.tgz#d2775fea15411f5f5aeda2a5e02c2f36440f6d55"
+  integrity sha512-PCeuAH4AWUo2O5+ksW4pL9v5xJAcIKPUPfIhZBcG1RKv/0+dvaWTQK1Nrau8d67dp65fOqbeMdoil+6PedyEPQ==
+  dependencies:
+    chalk "^4.0.0"
+    diff-sequences "^27.0.6"
+    jest-get-type "^27.3.1"
+    pretty-format "^27.3.1"
+
 jest-docblock@^24.3.0:
   version "24.9.0"
   resolved "https://registry.yarnpkg.com/jest-docblock/-/jest-docblock-24.9.0.tgz#7970201802ba560e1c4092cc25cbedf5af5a8ce2"
@@ -9747,6 +9770,11 @@ jest-get-type@^26.3.0:
   resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-26.3.0.tgz#e97dc3c3f53c2b406ca7afaed4493b1d099199e0"
   integrity sha512-TpfaviN1R2pQWkIihlfEanwOXK0zcxrKEE4MlU6Tn7keoXdN6/3gK/xl0yEh8DOunn5pOVGKf8hB4R9gVh04ig==
 
+jest-get-type@^27.3.1:
+  version "27.3.1"
+  resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-27.3.1.tgz#a8a2b0a12b50169773099eee60a0e6dd11423eff"
+  integrity sha512-+Ilqi8hgHSAdhlQ3s12CAVNd8H96ZkQBfYoXmArzZnOfAtVAJEiPDBirjByEblvG/4LPJmkL+nBqPO3A1YJAEg==
+
 jest-haste-map@^24.9.0:
   version "24.9.0"
   resolved "https://registry.yarnpkg.com/jest-haste-map/-/jest-haste-map-24.9.0.tgz#b38a5d64274934e21fa417ae9a9fbeb77ceaac7d"
@@ -13107,7 +13135,7 @@ pretty-format@^26.1.0:
     ansi-styles "^4.0.0"
     react-is "^16.12.0"
 
-pretty-format@^27.0.2:
+pretty-format@^27.0.0, pretty-format@^27.0.2, pretty-format@^27.3.1:
   version "27.3.1"
   resolved "https://registry.yarnpkg.com/pretty-format/-/pretty-format-27.3.1.tgz#7e9486365ccdd4a502061fa761d3ab9ca1b78df5"
   integrity sha512-DR/c+pvFc52nLimLROYjnXPtolawm+uWDxr4FjuLDLUn+ktWnSN851KoHwHzzqq6rfCOjkzN8FLgDrSub6UDuA==