diff --git a/extension/src/background/store/apiMiddleware.ts b/extension/src/background/store/apiMiddleware.ts
index 06c098d2..e88c841b 100644
--- a/extension/src/background/store/apiMiddleware.ts
+++ b/extension/src/background/store/apiMiddleware.ts
@@ -18,7 +18,7 @@ import syncOptions, {
 } from '../../options/syncOptions';
 import openDevToolsWindow, { DevToolsPosition } from '../openWindow';
 import { getReport } from '../logging';
-import { Action, Dispatch, MiddlewareAPI } from 'redux';
+import { Action, Dispatch, Middleware } from 'redux';
 import type {
   ContentScriptToBackgroundMessage,
   SplitMessage,
@@ -670,10 +670,10 @@ declare global {
 
 window.syncOptions = syncOptions(toAllTabs); // Expose to the options page
 
-export default function api(
-  store: MiddlewareAPI<Dispatch<BackgroundAction>, BackgroundState>,
-) {
-  return (next: Dispatch<BackgroundAction>) => (action: BackgroundAction) => {
+const api: Middleware<{}, BackgroundState, Dispatch<BackgroundAction>> =
+  (store) => (next) => (untypedAction) => {
+    const action = untypedAction as BackgroundAction;
+
     if (action.type === LIFTED_ACTION) toContentScript(action);
     else if (action.type === TOGGLE_PERSIST) {
       togglePersist();
@@ -684,4 +684,5 @@ export default function api(
     }
     return next(action);
   };
-}
+
+export default api;
diff --git a/extension/src/background/store/backgroundReducer.ts b/extension/src/background/store/backgroundReducer.ts
index 01ca5a02..fb0f5a7c 100644
--- a/extension/src/background/store/backgroundReducer.ts
+++ b/extension/src/background/store/backgroundReducer.ts
@@ -1,14 +1,17 @@
 import { combineReducers, Reducer } from 'redux';
 import { instances, InstancesState } from '@redux-devtools/app';
-import type { BackgroundAction } from './backgroundStore';
+import { BackgroundAction } from './backgroundStore';
 
 export interface BackgroundState {
   readonly instances: InstancesState;
 }
 
-const rootReducer: Reducer<BackgroundState, BackgroundAction> =
-  combineReducers<BackgroundState>({
-    instances,
-  });
+const rootReducer: Reducer<
+  BackgroundState,
+  BackgroundAction,
+  Partial<BackgroundState>
+> = combineReducers({
+  instances,
+}) as any;
 
 export default rootReducer;
diff --git a/extension/src/background/store/backgroundStore.ts b/extension/src/background/store/backgroundStore.ts
index 21187ce8..595f9479 100644
--- a/extension/src/background/store/backgroundStore.ts
+++ b/extension/src/background/store/backgroundStore.ts
@@ -1,4 +1,4 @@
-import { createStore, applyMiddleware, PreloadedState } from 'redux';
+import { createStore, applyMiddleware } from 'redux';
 import {
   CustomAction,
   DispatchAction,
@@ -60,7 +60,7 @@ export type BackgroundAction =
   | DisconnectedAction;
 
 export default function configureStore(
-  preloadedState?: PreloadedState<BackgroundState>,
+  preloadedState?: Partial<BackgroundState>,
 ) {
   return createStore(rootReducer, preloadedState, applyMiddleware(api));
   /*
diff --git a/extension/src/devpanel/store/panelReducer.ts b/extension/src/devpanel/store/panelReducer.ts
index 9dc14c71..a6b75a1a 100644
--- a/extension/src/devpanel/store/panelReducer.ts
+++ b/extension/src/devpanel/store/panelReducer.ts
@@ -30,16 +30,19 @@ export interface StoreStateWithoutSocket {
   readonly stateTreeSettings: StateTreeSettings;
 }
 
-const rootReducer: Reducer<StoreStateWithoutSocket, StoreAction> =
-  combineReducers<StoreStateWithoutSocket>({
-    instances,
-    monitor,
-    reports,
-    notification,
-    section,
-    theme,
-    connection,
-    stateTreeSettings,
-  });
+const rootReducer: Reducer<
+  StoreStateWithoutSocket,
+  StoreAction,
+  Partial<StoreStateWithoutSocket>
+> = combineReducers({
+  instances,
+  monitor,
+  reports,
+  notification,
+  section,
+  theme,
+  connection,
+  stateTreeSettings,
+}) as any;
 
 export default rootReducer;
diff --git a/extension/src/devpanel/store/panelStore.ts b/extension/src/devpanel/store/panelStore.ts
index e8ce7ca5..018b7704 100644
--- a/extension/src/devpanel/store/panelStore.ts
+++ b/extension/src/devpanel/store/panelStore.ts
@@ -1,4 +1,4 @@
-import { createStore, applyMiddleware, Reducer } from 'redux';
+import { createStore, applyMiddleware, Reducer, Store } from 'redux';
 import localForage from 'localforage';
 import { persistReducer, persistStore } from 'redux-persist';
 import { exportStateMiddleware, StoreAction } from '@redux-devtools/app';
@@ -23,6 +23,6 @@ export default function configureStore(
     panelDispatcher(bgConnection),
   );
   const store = createStore(persistedReducer, enhancer);
-  const persistor = persistStore(store);
+  const persistor = persistStore(store as Store);
   return { store, persistor };
 }
diff --git a/extension/src/devpanel/store/panelSyncMiddleware.ts b/extension/src/devpanel/store/panelSyncMiddleware.ts
index 7c31fcca..278aef75 100644
--- a/extension/src/devpanel/store/panelSyncMiddleware.ts
+++ b/extension/src/devpanel/store/panelSyncMiddleware.ts
@@ -7,31 +7,33 @@ import {
   TOGGLE_PERSIST,
   UPDATE_STATE,
 } from '@redux-devtools/app';
-import { Dispatch, MiddlewareAPI } from 'redux';
+import { Dispatch, Middleware } from 'redux';
 
-function panelDispatcher(bgConnection: chrome.runtime.Port) {
+function panelDispatcher(
+  bgConnection: chrome.runtime.Port,
+): Middleware<{}, StoreState, Dispatch<StoreAction>> {
   let autoselected = false;
   const tabId = chrome.devtools.inspectedWindow.tabId;
 
-  return (store: MiddlewareAPI<Dispatch<StoreAction>, StoreState>) =>
-    (next: Dispatch<StoreAction>) =>
-    (action: StoreAction) => {
-      const result = next(action);
-      if (!autoselected && action.type === UPDATE_STATE && tabId) {
-        autoselected = true;
-        const connections = store.getState().instances.connections[tabId];
-        if (connections && connections.length === 1) {
-          next({ type: SELECT_INSTANCE, selected: connections[0] });
-        }
+  return (store) => (next) => (untypedAction) => {
+    const action = untypedAction as StoreAction;
+
+    const result = next(action);
+    if (!autoselected && action.type === UPDATE_STATE && tabId) {
+      autoselected = true;
+      const connections = store.getState().instances.connections[tabId];
+      if (connections && connections.length === 1) {
+        next({ type: SELECT_INSTANCE, selected: connections[0] });
       }
-      if (action.type === LIFTED_ACTION || action.type === TOGGLE_PERSIST) {
-        const instances = store.getState().instances;
-        const instanceId = getActiveInstance(instances);
-        const id = instances.options[instanceId].connectionId;
-        bgConnection.postMessage({ ...action, instanceId, id });
-      }
-      return result;
-    };
+    }
+    if (action.type === LIFTED_ACTION || action.type === TOGGLE_PERSIST) {
+      const instances = store.getState().instances;
+      const instanceId = getActiveInstance(instances);
+      const id = instances.options[instanceId].connectionId;
+      bgConnection.postMessage({ ...action, instanceId, id });
+    }
+    return result;
+  };
 }
 
 export default panelDispatcher;
diff --git a/extension/src/pageScript/index.ts b/extension/src/pageScript/index.ts
index 00a4df49..39b00235 100644
--- a/extension/src/pageScript/index.ts
+++ b/extension/src/pageScript/index.ts
@@ -9,7 +9,6 @@ import {
   Action,
   ActionCreator,
   Dispatch,
-  PreloadedState,
   Reducer,
   StoreEnhancer,
   StoreEnhancerStoreCreator,
@@ -526,34 +525,28 @@ function __REDUX_DEVTOOLS_EXTENSION__<S, A extends Action<string>>(
     relayState(liftedState);
   }
 
-  const enhance =
-    (): StoreEnhancer =>
-    <NextExt, NextStateExt>(
-      next: StoreEnhancerStoreCreator<NextExt, NextStateExt>,
-    ): any => {
-      return <S2 extends S, A2 extends A>(
-        reducer_: Reducer<S2, A2>,
-        initialState_?: PreloadedState<S2>,
-      ) => {
-        if (!isAllowed(window.devToolsOptions)) {
-          return next(reducer_, initialState_);
-        }
+  const enhance = (): StoreEnhancer => (next) => {
+    return <S2, A2 extends Action<string>, PreloadedState>(
+      reducer_: Reducer<S2, A2, PreloadedState>,
+      initialState_?: PreloadedState | undefined,
+    ) => {
+      if (!isAllowed(window.devToolsOptions)) {
+        return next(reducer_, initialState_);
+      }
 
-        store = stores[instanceId] = configureStore(
-          next as StoreEnhancerStoreCreator,
-          monitor.reducer,
-          {
-            ...config,
-            maxAge: getMaxAge as any,
-          },
-        )(reducer_, initialState_) as any;
+      store = stores[instanceId] = (
+        configureStore(next, monitor.reducer, {
+          ...config,
+          maxAge: getMaxAge as any,
+        }) as any
+      )(reducer_, initialState_) as any;
 
-        if (isInIframe()) setTimeout(init, 3000);
-        else init();
+      if (isInIframe()) setTimeout(init, 3000);
+      else init();
 
-        return store;
-      };
+      return store as any;
     };
+  };
 
   return enhance();
 }
@@ -598,11 +591,11 @@ export type InferComposedStoreExt<StoreEnhancers> = StoreEnhancers extends [
   ? HeadStoreEnhancer extends StoreEnhancer<infer StoreExt>
     ? StoreExt & InferComposedStoreExt<RestStoreEnhancers>
     : never
-  : unknown;
+  : {};
 
 const extensionCompose =
   (config: Config) =>
-  <StoreEnhancers extends readonly StoreEnhancer<unknown>[]>(
+  <StoreEnhancers extends readonly StoreEnhancer[]>(
     ...funcs: StoreEnhancers
   ): StoreEnhancer<InferComposedStoreExt<StoreEnhancers>> => {
     // @ts-ignore FIXME
@@ -619,10 +612,10 @@ const extensionCompose =
 interface ReduxDevtoolsExtensionCompose {
   (
     config: Config,
-  ): <StoreEnhancers extends readonly StoreEnhancer<unknown>[]>(
+  ): <StoreEnhancers extends readonly StoreEnhancer[]>(
     ...funcs: StoreEnhancers
   ) => StoreEnhancer<InferComposedStoreExt<StoreEnhancers>>;
-  <StoreEnhancers extends readonly StoreEnhancer<unknown>[]>(
+  <StoreEnhancers extends readonly StoreEnhancer[]>(
     ...funcs: StoreEnhancers
   ): StoreEnhancer<InferComposedStoreExt<StoreEnhancers>>;
 }
@@ -635,24 +628,22 @@ declare global {
 
 function reduxDevtoolsExtensionCompose(
   config: Config,
-): <StoreEnhancers extends readonly StoreEnhancer<unknown>[]>(
+): <StoreEnhancers extends readonly StoreEnhancer[]>(
   ...funcs: StoreEnhancers
 ) => StoreEnhancer<InferComposedStoreExt<StoreEnhancers>>;
 function reduxDevtoolsExtensionCompose<
-  StoreEnhancers extends readonly StoreEnhancer<unknown>[],
+  StoreEnhancers extends readonly StoreEnhancer[],
 >(
   ...funcs: StoreEnhancers
 ): StoreEnhancer<InferComposedStoreExt<StoreEnhancers>>;
-function reduxDevtoolsExtensionCompose(
-  ...funcs: [Config] | StoreEnhancer<unknown>[]
-) {
+function reduxDevtoolsExtensionCompose(...funcs: [Config] | StoreEnhancer[]) {
   if (funcs.length === 0) {
     return __REDUX_DEVTOOLS_EXTENSION__();
   }
   if (funcs.length === 1 && typeof funcs[0] === 'object') {
     return extensionCompose(funcs[0]);
   }
-  return extensionCompose({})(...(funcs as StoreEnhancer<unknown>[]));
+  return extensionCompose({})(...(funcs as StoreEnhancer[]));
 }
 
 window.__REDUX_DEVTOOLS_EXTENSION_COMPOSE__ = reduxDevtoolsExtensionCompose;
diff --git a/extension/src/window/store/instanceSelectorMiddleware.ts b/extension/src/window/store/instanceSelectorMiddleware.ts
index e10879bc..7587cb8d 100644
--- a/extension/src/window/store/instanceSelectorMiddleware.ts
+++ b/extension/src/window/store/instanceSelectorMiddleware.ts
@@ -1,4 +1,4 @@
-import { Dispatch, MiddlewareAPI } from 'redux';
+import { Dispatch, Middleware, MiddlewareAPI } from 'redux';
 import {
   SELECT_INSTANCE,
   StoreAction,
@@ -9,7 +9,7 @@ import {
 function selectInstance(
   tabId: number,
   store: MiddlewareAPI<Dispatch<StoreAction>, StoreState>,
-  next: Dispatch<StoreAction>,
+  next: (action: unknown) => unknown,
 ) {
   const instances = store.getState().instances;
   if (instances.current === 'default') return;
@@ -33,10 +33,10 @@ function getCurrentTabId(next: (tabId: number) => void) {
   );
 }
 
-export default function popupSelector(
-  store: MiddlewareAPI<Dispatch<StoreAction>, StoreState>,
-) {
-  return (next: Dispatch<StoreAction>) => (action: StoreAction) => {
+const popupSelector: Middleware<{}, StoreState, Dispatch<StoreAction>> =
+  (store) => (next) => (untypedAction) => {
+    const action = untypedAction as StoreAction;
+
     const result = next(action);
     if (action.type === UPDATE_STATE) {
       if (chrome.devtools && chrome.devtools.inspectedWindow) {
@@ -47,4 +47,5 @@ export default function popupSelector(
     }
     return result;
   };
-}
+
+export default popupSelector;
diff --git a/extension/src/window/store/windowReducer.ts b/extension/src/window/store/windowReducer.ts
index 458b2760..dab281c9 100644
--- a/extension/src/window/store/windowReducer.ts
+++ b/extension/src/window/store/windowReducer.ts
@@ -13,17 +13,20 @@ import {
 import instances from './instancesReducer';
 import type { WindowStoreAction } from './windowStore';
 
-const rootReducer: Reducer<StoreState, WindowStoreAction> =
-  combineReducers<StoreState>({
-    instances,
-    monitor,
-    socket,
-    reports,
-    notification,
-    section,
-    theme,
-    connection,
-    stateTreeSettings,
-  });
+const rootReducer: Reducer<
+  StoreState,
+  WindowStoreAction,
+  Partial<StoreState>
+> = combineReducers({
+  instances,
+  monitor,
+  socket,
+  reports,
+  notification,
+  section,
+  theme,
+  connection,
+  stateTreeSettings,
+}) as any;
 
 export default rootReducer;
diff --git a/extension/src/window/store/windowStore.ts b/extension/src/window/store/windowStore.ts
index 43cea9c5..ce746a92 100644
--- a/extension/src/window/store/windowStore.ts
+++ b/extension/src/window/store/windowStore.ts
@@ -69,7 +69,7 @@ export default function configureStore(
     );
   }
   const store = createStore(persistedReducer, enhancer);
-  const persistor = persistStore(store, null, () => {
+  const persistor = persistStore(store as Store, null, () => {
     if (store.getState().connection.type !== 'disabled') {
       store.dispatch({
         type: CONNECT_REQUEST,
diff --git a/extension/src/window/store/windowSyncMiddleware.ts b/extension/src/window/store/windowSyncMiddleware.ts
index 6f9f9cf7..9cdcdfa8 100644
--- a/extension/src/window/store/windowSyncMiddleware.ts
+++ b/extension/src/window/store/windowSyncMiddleware.ts
@@ -6,16 +6,19 @@ import {
   TOGGLE_PERSIST,
   UPDATE_STATE,
 } from '@redux-devtools/app';
-import { Dispatch, MiddlewareAPI, Store } from 'redux';
+import { Dispatch, Middleware, Store } from 'redux';
 import type { BackgroundState } from '../../background/store/backgroundReducer';
-import type { WindowStoreAction } from './windowStore';
 import type { BackgroundAction } from '../../background/store/backgroundStore';
 
 const syncStores =
-  (baseStore: Store<BackgroundState, BackgroundAction>) =>
-  (store: MiddlewareAPI<Dispatch<StoreAction>, StoreState>) =>
-  (next: Dispatch<WindowStoreAction>) =>
-  (action: StoreAction) => {
+  (
+    baseStore: Store<BackgroundState, BackgroundAction>,
+  ): Middleware<{}, StoreState, Dispatch<StoreAction>> =>
+  (store) =>
+  (next) =>
+  (untypedAction) => {
+    const action = untypedAction as StoreAction;
+
     if (action.type === UPDATE_STATE) {
       return next({
         ...action,