diff --git a/.gitignore b/.gitignore
index 7bca893d..67a1d7cb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,5 @@ lerna-debug.log*
 # when working with contributors
 package-lock.json
 yarn.lock
+
+.vercel
diff --git a/docs/api/options.md b/docs/api/options.md
index 6ca6ac61..64d353e9 100644
--- a/docs/api/options.md
+++ b/docs/api/options.md
@@ -41,7 +41,7 @@ A function that returns a promise. It is automatically invoked in `componentDidM
 
 > `function(args: any[], props: Object, controller: AbortController): Promise`
 
-A function that returns a promise. This is invoked only by manually calling `run(...args)`. Receives the same arguments as `promiseFn`, as well as any arguments to `run` which are passed through as an array. The `deferFn` is commonly used to send data to the server following a user action, such as submitting a form. You can use this in conjunction with `promiseFn` to fill the form with existing data, then updating it on submit with `deferFn`.
+A function that returns a promise. This is invoked only by manually calling `run(...args)`. Any arguments to `run` are passed-through as an array via `args`, so you can pass data through either `args` or `props`, as needed. The `deferFn` is commonly used to send data to the server following a user action, such as submitting a form. You can use this in conjunction with `promiseFn` to fill the form with existing data, then updating it on submit with `deferFn`.
 
 > Be aware that when using both `promiseFn` and `deferFn`, the shape of their fulfilled value should match, because they both update the same `data`.
 
@@ -87,7 +87,7 @@ Callback function invoked when a promise is cancelled, either manually using `ca
 
 > `function(state: any, action: Object, internalReducer: function(state: any, action: Object))`
 
-State reducer to take full control over state updates by wrapping the [internal reducer](https://github.com/async-library/react-async/blob/master/src/reducer.js). It receives the current state, the dispatched action and the internal reducer. You probably want to invoke the internal reducer at some point.
+State reducer to take full control over state updates by wrapping the [internal reducer](https://github.com/async-library/react-async/blob/master/packages/react-async/src/reducer.ts). It receives the current state, the dispatched action and the internal reducer. You probably want to invoke the internal reducer at some point.
 
 > This is a power feature which loosely follows the [state reducer pattern](https://kentcdodds.com/blog/the-state-reducer-pattern). It allows you to control state changes by intercepting actions before they are handled, or by overriding or enhancing the reducer itself.
 
diff --git a/docs/introduction.md b/docs/introduction.md
index 7b3e2879..2eb4c3e9 100644
--- a/docs/introduction.md
+++ b/docs/introduction.md
@@ -29,4 +29,4 @@ impact on performance and usability. When Suspense lands, React Async will make
 you can already **start using React Async right now**, and in a later update, you'll **get Suspense features for free**.
 In fact, React Async already has experimental support for Suspense, by passing the `suspense` option.
 
-[concurrent react]: https://github.com/sw-yx/fresh-concurrent-react/blob/master/Intro.md#introduction-what-is-concurrent-react
+[concurrent react]: https://reactjs.org/docs/concurrent-mode-intro.html
diff --git a/package.json b/package.json
index e2d06a47..2c69cc71 100644
--- a/package.json
+++ b/package.json
@@ -4,6 +4,7 @@
   "author": "Gert Hengeveld <info@ghengeveld.nl>",
   "license": "ISC",
   "homepage": "https://async-library.com",
+  "browserslist": "last 2 Firefox versions",
   "repository": "git+https://github.com/async-library/react-async.git",
   "workspaces": [
     "examples/*",
@@ -13,7 +14,7 @@
     "bootstrap": "yarn build:packages && yarn workspaces run bootstrap",
     "clean": "lerna clean",
     "start": "run-p start:*",
-    "start:examples": "now dev",
+    "start:examples": "vercel dev",
     "start:storybook": "start-storybook -p 6006",
     "lint": "eslint packages/*/src/*.{js,ts,tsx}",
     "test": "jest packages/*/src/*.spec.js",
@@ -25,24 +26,24 @@
     "test:latest": "yarn add -D -W react@latest react-dom@latest && yarn resolutions:fix-react && yarn test",
     "test:compat": "yarn test:backwards && yarn test:forwards && yarn test:latest",
     "test:examples": "CI=1 lerna run --scope '*-example' test -- --passWithNoTests --watchAll=false",
-    "test:chromatic": "chromatic --app-code iiua39bmt0j --build-script-name build:storybook --exit-zero-on-changes",
+    "test:chromatic": "chromatic -t iiua39bmt0j -b build:storybook --exit-zero-on-changes",
     "resolutions:fix-react": "jq '.resolutions.react = .devDependencies.react|.resolutions.\"react-dom\"=.devDependencies.react' package.json > package.json.new && mv package.json.new package.json && yarn install",
     "ci": "yarn lint && yarn test:compat && yarn test:examples",
     "build:packages": "lerna run --scope 'react-async*' build",
     "build:examples": "lerna run --scope '*-example' build",
     "build:storybook": "build-storybook -o storybook",
-    "deploy:examples": "now --prod --scope async-library --token $NOW_API_TOKEN",
+    "deploy:examples": "vercel --prod --scope async-library --token $NOW_API_TOKEN",
     "bump": "lerna version -m 'Bump' --no-git-tag-version --no-push",
     "postbump": "yarn build:packages"
   },
   "devDependencies": {
-    "@babel/core": "7.8.6",
+    "@babel/core": "7.9.6",
     "@babel/plugin-proposal-class-properties": "7.8.3",
-    "@babel/plugin-proposal-object-rest-spread": "7.8.3",
-    "@babel/plugin-transform-runtime": "7.8.3",
-    "@babel/preset-env": "7.8.7",
-    "@babel/preset-react": "7.8.3",
-    "@babel/preset-typescript": "7.8.3",
+    "@babel/plugin-proposal-object-rest-spread": "7.9.6",
+    "@babel/plugin-transform-runtime": "7.9.6",
+    "@babel/preset-env": "7.9.6",
+    "@babel/preset-react": "7.9.4",
+    "@babel/preset-typescript": "7.9.0",
     "@pika/pack": "0.5.0",
     "@pika/plugin-build-node": "0.9.2",
     "@pika/plugin-build-types": "0.9.2",
@@ -51,36 +52,33 @@
     "@pika/plugin-bundle-types": "0.9.2",
     "@pika/plugin-standard-pkg": "0.9.2",
     "@pika/plugin-ts-standard-pkg": "0.9.2",
-    "@storybook/react": "5.3.14",
+    "@storybook/react": "5.3.18",
     "@testing-library/jest-dom": "4.2.4",
-    "@testing-library/react": "9.4.1",
-    "@typescript-eslint/eslint-plugin": "2.22.0",
-    "@typescript-eslint/parser": "2.22.0",
+    "@testing-library/react": "9.5.0",
+    "@typescript-eslint/eslint-plugin": "2.33.0",
+    "@typescript-eslint/parser": "2.33.0",
     "babel-eslint": "10.1.0",
     "babel-jest": "24.9.0",
-    "babel-loader": "8.0.6",
+    "babel-loader": "8.1.0",
+    "chromatic": "5.2.0",
     "copyfiles": "2.2.0",
     "eslint": "6.8.0",
-    "eslint-config-prettier": "6.10.0",
-    "eslint-plugin-jest": "23.8.1",
-    "eslint-plugin-prettier": "3.1.2",
+    "eslint-config-prettier": "6.11.0",
+    "eslint-plugin-jest": "23.11.0",
+    "eslint-plugin-prettier": "3.1.3",
     "eslint-plugin-promise": "4.2.1",
-    "eslint-plugin-react": "7.18.3",
-    "eslint-plugin-react-hooks": "2.5.0",
+    "eslint-plugin-react": "7.19.0",
+    "eslint-plugin-react-hooks": "2.5.1",
     "jest": "24.9.0",
     "lerna": "3.20.2",
-    "node-jq": "1.11.0",
-    "now": "16.7.3",
+    "node-jq": "1.11.1",
+    "vercel": "20.1.2",
     "npm-run-all": "4.1.5",
     "prettier": "1.19.1",
     "prop-types": "15.7.2",
-    "react": "16.13.0",
+    "react": "17.0.2",
     "react-async": "10.0.0-alpha.0",
-    "react-dom": "16.13.0",
-    "storybook-chromatic": "3.5.2",
+    "react-dom": "17.0.2",
     "typescript": "3.8.3"
-  },
-  "resolutions": {
-    "@types/react": "16.9.13"
   }
 }
diff --git a/packages/react-async/src/globalScope.ts b/packages/react-async/src/globalScope.ts
index 8fd3ffbd..91a0067e 100644
--- a/packages/react-async/src/globalScope.ts
+++ b/packages/react-async/src/globalScope.ts
@@ -11,9 +11,10 @@ declare type GlobalScope = {
  * This file is excluded from coverage reporting because these globals are environment-specific so we can't test them all.
  */
 const globalScope = (() => {
+  const glbl = global as any
   if (typeof self === "object" && self.self === self) return self
-  if (typeof global === "object" && global.global === global) return global
-  if (typeof global === "object" && global.GLOBAL === global) return global
+  if (typeof glbl === "object" && glbl.global === glbl) return glbl
+  if (typeof glbl === "object" && glbl.GLOBAL === glbl) return glbl
   return {} // fallback that relies on imported modules to be singletons
 })() as GlobalScope
 
diff --git a/packages/react-async/src/specs.js b/packages/react-async/src/specs.js
index 14054789..3517f903 100644
--- a/packages/react-async/src/specs.js
+++ b/packages/react-async/src/specs.js
@@ -283,7 +283,7 @@ export const withPromiseFn = (Async, abortCtrl) => () => {
     expect(promiseFn).toHaveBeenCalledTimes(1)
     fireEvent.click(getByText("reload"))
     expect(promiseFn).toHaveBeenCalledTimes(2)
-    expect(abortCtrl.abort).toHaveBeenCalledTimes(1)
+    expect(abortCtrl.abort).toHaveBeenCalled()
   })
 
   test("re-runs the promise with new props when the value of `watch` changes", () => {
@@ -404,7 +404,7 @@ export const withPromiseFn = (Async, abortCtrl) => () => {
     rerender(<Async onResolve={onResolve} />)
     await sleep(10)
     expect(onResolve).not.toHaveBeenCalled()
-    expect(abortCtrl.abort).toHaveBeenCalledTimes(1)
+    expect(abortCtrl.abort).toHaveBeenCalled()
   })
 
   test("does not run `promiseFn` on mount when `initialValue` is provided", async () => {
diff --git a/packages/react-async/src/useAsync.tsx b/packages/react-async/src/useAsync.tsx
index b3eb22d9..291e3709 100644
--- a/packages/react-async/src/useAsync.tsx
+++ b/packages/react-async/src/useAsync.tsx
@@ -10,6 +10,7 @@ import {
 } from "./reducer"
 
 import {
+  AsyncAction,
   AsyncOptions,
   AsyncState,
   AbstractState,
@@ -60,7 +61,9 @@ function useAsync<T>(arg1: AsyncOptions<T> | PromiseFn<T>, arg2?: AsyncOptions<T
   const { devToolsDispatcher } = globalScope.__REACT_ASYNC__
   const { reducer, dispatcher = devToolsDispatcher } = options
   const [state, _dispatch] = useReducer(
-    reducer ? (state, action) => reducer(state, action, asyncReducer) : asyncReducer,
+    reducer
+      ? (state: AsyncState<T>, action: AsyncAction<T>) => reducer(state, action, asyncReducer)
+      : asyncReducer,
     options,
     init
   )
@@ -336,5 +339,7 @@ const unsupported = () => {
   )
 }
 
+// @ts-ignore
 export default useEffect ? useAsync : unsupported
+// @ts-ignore
 export const useFetch = useEffect ? useAsyncFetch : unsupported
diff --git a/packages/react-async/tsconfig.json b/packages/react-async/tsconfig.json
index f261ce40..89209d65 100644
--- a/packages/react-async/tsconfig.json
+++ b/packages/react-async/tsconfig.json
@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "es2019",
+    "target": "es2020",
     "module": "esnext",
     "allowJs": false,
     "checkJs": false,
diff --git a/now.json b/vercel.json
similarity index 100%
rename from now.json
rename to vercel.json