diff --git a/types/async/index.d.ts b/types/async/index.d.ts
index 961dd73ebb..e6cfd3bcaa 100644
--- a/types/async/index.d.ts
+++ b/types/async/index.d.ts
@@ -2,34 +2,34 @@
 // Project: https://github.com/caolan/async
 // Definitions by: Boris Yankov <https://github.com/borisyankov>, Arseniy Maximov <https://github.com/kern0>, Joe Herman <https://github.com/Penryn>, Angus Fenying <https://github.com/fenying>, Pascal Martin <https://github.com/pascalmartin>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.1
+// TypeScript Version: 2.3
 
 export as namespace async;
 
 export interface Dictionary<T> { [key: string]: T; }
 export type IterableCollection<T> = T[] | IterableIterator<T> | Dictionary<T>
 
-export interface ErrorCallback<T> { (err?: T): void; }
-export interface AsyncBooleanResultCallback<E> { (err?: E, truthValue?: boolean): void; }
-export interface AsyncResultCallback<T, E> { (err?: E, result?: T): void; }
-export interface AsyncResultArrayCallback<T, E> { (err?: E, results?: Array<T | undefined>): void; }
-export interface AsyncResultObjectCallback<T, E> { (err: E | undefined, results: Dictionary<T | undefined>): void; }
+export interface ErrorCallback<E = Error> { (err?: E | null): void; }
+export interface AsyncBooleanResultCallback<E = Error> { (err?: E | null, truthValue?: boolean): void; }
+export interface AsyncResultCallback<T, E = Error> { (err?: E | null, result?: T): void; }
+export interface AsyncResultArrayCallback<T, E = Error> { (err?: E | null, results?: Array<T | undefined>): void; }
+export interface AsyncResultObjectCallback<T, E = Error> { (err: E | undefined, results: Dictionary<T | undefined>): void; }
 
-export interface AsyncFunction<T, E> { (callback: (err?: E, result?: T) => void): void; }
-export interface AsyncFunctionEx<T, E> { (callback: (err?: E, ...results: T[]) => void): void; }
-export interface AsyncIterator<T, E> { (item: T, callback: ErrorCallback<E>): void; }
-export interface AsyncForEachOfIterator<T, E> { (item: T, key: number|string, callback: ErrorCallback<E>): void; }
-export interface AsyncResultIterator<T, R, E> { (item: T, callback: AsyncResultCallback<R, E>): void; }
-export interface AsyncMemoIterator<T, R, E> { (memo: R | undefined, item: T, callback: AsyncResultCallback<R, E>): void; }
-export interface AsyncBooleanIterator<T, E> { (item: T, callback: AsyncBooleanResultCallback<E>): void; }
+export interface AsyncFunction<T, E = Error> { (callback: (err?: E | null, result?: T) => void): void; }
+export interface AsyncFunctionEx<T, E = Error> { (callback: (err?: E | null, ...results: T[]) => void): void; }
+export interface AsyncIterator<T, E = Error> { (item: T, callback: ErrorCallback<E>): void; }
+export interface AsyncForEachOfIterator<T, E = Error> { (item: T, key: number|string, callback: ErrorCallback<E>): void; }
+export interface AsyncResultIterator<T, R, E = Error> { (item: T, callback: AsyncResultCallback<R, E>): void; }
+export interface AsyncMemoIterator<T, R, E = Error> { (memo: R | undefined, item: T, callback: AsyncResultCallback<R, E>): void; }
+export interface AsyncBooleanIterator<T, E = Error> { (item: T, callback: AsyncBooleanResultCallback<E>): void; }
 
-export interface AsyncWorker<T, E> { (task: T, callback: ErrorCallback<E>): void; }
-export interface AsyncVoidFunction<E> { (callback: ErrorCallback<E>): void; }
+export interface AsyncWorker<T, E = Error> { (task: T, callback: ErrorCallback<E>): void; }
+export interface AsyncVoidFunction<E = Error> { (callback: ErrorCallback<E>): void; }
 
 export type AsyncAutoTasks<R extends Dictionary<any>, E> = { [K in keyof R]: AsyncAutoTask<R[K], R, E> }
 export type AsyncAutoTask<R1, R extends Dictionary<any>, E> = AsyncAutoTaskFunctionWithoutDependencies<R1, E> | (keyof R | AsyncAutoTaskFunction<R1, R, E>)[];
-export interface AsyncAutoTaskFunctionWithoutDependencies<R1, E> { (cb: AsyncResultCallback<R1, E> | ErrorCallback<E>): void; }
-export interface AsyncAutoTaskFunction<R1, R extends Dictionary<any>, E> { (results: R, cb: AsyncResultCallback<R1, E> | ErrorCallback<E>): void; }
+export interface AsyncAutoTaskFunctionWithoutDependencies<R1, E = Error> { (cb: AsyncResultCallback<R1, E> | ErrorCallback<E>): void; }
+export interface AsyncAutoTaskFunction<R1, R extends Dictionary<any>, E = Error> { (results: R, cb: AsyncResultCallback<R1, E> | ErrorCallback<E>): void; }
 
 export interface AsyncQueue<T> {
     length(): number;
@@ -37,9 +37,8 @@ export interface AsyncQueue<T> {
     running(): number;
     idle(): boolean;
     concurrency: number;
-    push<E>(task: T | T[], callback?: ErrorCallback<E>): void;
-    push<R,E>(task: T, callback?: AsyncResultCallback<R, E>): void;
-    unshift<E>(task: T | T[], callback?: ErrorCallback<E>): void;
+    push<R,E = Error>(task: T | T[], callback?: AsyncResultCallback<R, E>): void;
+    unshift<E = Error>(task: T | T[], callback?: ErrorCallback<E>): void;
     saturated: () => any;
     empty: () => any;
     drain: () => any;
@@ -61,7 +60,7 @@ export interface AsyncPriorityQueue<T> {
     concurrency: number;
     started: boolean;
     paused: boolean;
-    push<R,E>(task: T | T[], priority: number, callback?: AsyncResultArrayCallback<R, E>): void;
+    push<R,E = Error>(task: T | T[], priority: number, callback?: AsyncResultArrayCallback<R, E>): void;
     saturated: () => any;
     empty: () => any;
     drain: () => any;
@@ -94,112 +93,113 @@ export interface AsyncCargo {
 }
 
 // Collections
-export function each<T, E>(arr: IterableCollection<T>, iterator: AsyncIterator<T, E>, callback?: ErrorCallback<E>): void;
+export function each<T, E = Error>(arr: IterableCollection<T>, iterator: AsyncIterator<T, E>, callback?: ErrorCallback<E>): void;
 export const eachSeries: typeof each;
-export function eachLimit<T, E>(arr: IterableCollection<T>, limit: number, iterator: AsyncIterator<T, E>, callback?: ErrorCallback<E>): void;
+export function eachLimit<T, E = Error>(arr: IterableCollection<T>, limit: number, iterator: AsyncIterator<T, E>, callback?: ErrorCallback<E>): void;
 export const forEach: typeof each;
 export const forEachSeries: typeof each;
 export const forEachLimit: typeof eachLimit;
-export function forEachOf<T, E>(obj: IterableCollection<T>, iterator: AsyncForEachOfIterator<T, E>, callback?: ErrorCallback<E>): void;
+export function forEachOf<T, E = Error>(obj: IterableCollection<T>, iterator: AsyncForEachOfIterator<T, E>, callback?: ErrorCallback<E>): void;
 export const forEachOfSeries: typeof forEachOf;
-export function forEachOfLimit<T, E>(obj: IterableCollection<T>, limit: number, iterator: AsyncForEachOfIterator<T, E>, callback?: ErrorCallback<E>): void;
+export function forEachOfLimit<T, E = Error>(obj: IterableCollection<T>, limit: number, iterator: AsyncForEachOfIterator<T, E>, callback?: ErrorCallback<E>): void;
 export const eachOf: typeof forEachOf;
 export const eachOfSeries: typeof forEachOf;
 export const eachOfLimit: typeof forEachOfLimit;
-export function map<T, R, E>(arr: T[] | IterableIterator<T>, iterator: AsyncResultIterator<T, R, E>, callback?: AsyncResultArrayCallback<R, E>): void;
-export function map<T, R, E>(arr: Dictionary<T>, iterator: AsyncResultIterator<T, R, E>, callback?: AsyncResultArrayCallback<R, E>): void;
+export function map<T, R, E = Error>(arr: T[] | IterableIterator<T>, iterator: AsyncResultIterator<T, R, E>, callback?: AsyncResultArrayCallback<R, E>): void;
+export function map<T, R, E = Error>(arr: Dictionary<T>, iterator: AsyncResultIterator<T, R, E>, callback?: AsyncResultArrayCallback<R, E>): void;
 export const mapSeries: typeof map;
-export function mapLimit<T, R, E>(arr: IterableCollection<T>, limit: number, iterator: AsyncResultIterator<T, R, E>, callback?: AsyncResultArrayCallback<R, E>): void;
-export function mapValuesLimit<T, R, E>(obj: Dictionary<T>, limit: number, iteratee: (value: T, key: string, callback: AsyncResultCallback<R, E>) => void, callback: AsyncResultObjectCallback<R, E>): void;
-export function mapValues<T, R, E>(obj: Dictionary<T>, iteratee: (value: T, key: string, callback: AsyncResultCallback<R, E>) => void, callback: AsyncResultObjectCallback<R, E>): void;
+export function mapLimit<T, R, E = Error>(arr: IterableCollection<T>, limit: number, iterator: AsyncResultIterator<T, R, E>, callback?: AsyncResultArrayCallback<R, E>): void;
+export function mapValuesLimit<T, R, E = Error>(obj: Dictionary<T>, limit: number, iteratee: (value: T, key: string, callback: AsyncResultCallback<R, E>) => void, callback: AsyncResultObjectCallback<R, E>): void;
+export function mapValues<T, R, E = Error>(obj: Dictionary<T>, iteratee: (value: T, key: string, callback: AsyncResultCallback<R, E>) => void, callback: AsyncResultObjectCallback<R, E>): void;
 export const mapValuesSeries: typeof mapValues;
-export function filter<T, E>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultArrayCallback<T, E>): void;
+export function filter<T, E = Error>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultArrayCallback<T, E>): void;
 export const filterSeries: typeof filter;
-export function filterLimit<T, E>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultArrayCallback<T, E>): void;
+export function filterLimit<T, E = Error>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultArrayCallback<T, E>): void;
 export const select: typeof filter;
 export const selectSeries: typeof filter;
 export const selectLimit: typeof filterLimit;
 export const reject: typeof filter;
 export const rejectSeries: typeof filter;
 export const rejectLimit: typeof filterLimit;
-export function reduce<T, R, E>(arr: T[] | IterableIterator<T>, memo: R, iterator: AsyncMemoIterator<T, R, E>, callback?: AsyncResultCallback<R, E>): void;
+export function reduce<T, R, E = Error>(arr: T[] | IterableIterator<T>, memo: R, iterator: AsyncMemoIterator<T, R, E>, callback?: AsyncResultCallback<R, E>): void;
 export const inject: typeof reduce;
 export const foldl: typeof reduce;
 export const reduceRight: typeof reduce;
 export const foldr: typeof reduce;
-export function detect<T, E>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultCallback<T, E>): void;
+export function detect<T, E = Error>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultCallback<T, E>): void;
 export const detectSeries: typeof detect;
-export function detectLimit<T, E>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultCallback<T, E>): void;
+export function detectLimit<T, E = Error>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncResultCallback<T, E>): void;
 export const find: typeof detect;
 export const findSeries: typeof detect;
 export const findLimit: typeof detectLimit;
-export function sortBy<T, V, E>(arr: T[] | IterableIterator<T>, iterator: AsyncResultIterator<T, V, E>, callback?: AsyncResultArrayCallback<T, E>): void;
-export function some<T, E>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
+export function sortBy<T, V, E = Error>(arr: T[] | IterableIterator<T>, iterator: AsyncResultIterator<T, V, E>, callback?: AsyncResultArrayCallback<T, E>): void;
+export function some<T, E = Error>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
 export const someSeries: typeof some;
-export function someLimit<T, E>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
+export function someLimit<T, E = Error>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
 export const any: typeof some;
 export const anySeries: typeof someSeries;
 export const anyLimit: typeof someLimit;
-export function every<T, E>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
+export function every<T, E = Error>(arr: IterableCollection<T>, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
 export const everySeries: typeof every;
-export function everyLimit<T, E>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
+export function everyLimit<T, E = Error>(arr: IterableCollection<T>, limit: number, iterator: AsyncBooleanIterator<T, E>, callback?: AsyncBooleanResultCallback<E>): void;
 export const all: typeof every;
 export const allSeries: typeof every;
 export const allLimit: typeof everyLimit;
 
-export function concat<T, R, E>(arr: IterableCollection<T>, iterator: AsyncResultIterator<T, R[], E>, callback?: AsyncResultArrayCallback<R, E>): void;
-export function concatLimit<T, R, E>(arr: IterableCollection<T>, limit: number, iterator: AsyncResultIterator<T, R[], E>, callback?: AsyncResultArrayCallback<R, E>): void;
+export function concat<T, R, E = Error>(arr: IterableCollection<T>, iterator: AsyncResultIterator<T, R[], E>, callback?: AsyncResultArrayCallback<R, E>): void;
+export function concatLimit<T, R, E = Error>(arr: IterableCollection<T>, limit: number, iterator: AsyncResultIterator<T, R[], E>, callback?: AsyncResultArrayCallback<R, E>): void;
 export const concatSeries: typeof concat;
 
 // Control Flow
-export function series<T, E>(tasks: AsyncFunction<T, E>[], callback?: AsyncResultArrayCallback<T, E>): void;
-export function series<T, E>(tasks: Dictionary<AsyncFunction<T, E>>, callback?: AsyncResultObjectCallback<T, E>): void;
-export function parallel<T, E>(tasks: Array<AsyncFunction<T, E>>, callback?: AsyncResultArrayCallback<T, E>): void;
-export function parallel<T, E>(tasks: Dictionary<AsyncFunction<T, E>>, callback?: AsyncResultObjectCallback<T, E>): void;
-export function parallelLimit<T, E>(tasks: Array<AsyncFunction<T, E>>, limit: number, callback?: AsyncResultArrayCallback<T, E>): void;
-export function parallelLimit<T, E>(tasks: Dictionary<AsyncFunction<T, E>>, limit: number, callback?: AsyncResultObjectCallback<T, E>): void;
-export function whilst<E>(test: () => boolean, fn: AsyncVoidFunction<E>, callback: ErrorCallback<E>): void;
-export function doWhilst<T, E>(fn: AsyncFunctionEx<T, E>, test: (...results: T[]) => boolean, callback: ErrorCallback<E>): void;
-export function until<E>(test: () => boolean, fn: AsyncVoidFunction<E>, callback: ErrorCallback<E>): void;
-export function doUntil<T, E>(fn: AsyncFunctionEx<T, E>, test: (...results: T[]) => boolean, callback: ErrorCallback<E>): void;
-export function during<E>(test: (testCallback : AsyncBooleanResultCallback<E>) => void, fn: AsyncVoidFunction<E>, callback: ErrorCallback<E>): void;
-export function doDuring<E>(fn: AsyncVoidFunction<E>, test: (testCallback: AsyncBooleanResultCallback<E>) => void, callback: ErrorCallback<E>): void;
-export function forever<E>(next: (next : ErrorCallback<E>) => void, errBack: ErrorCallback<E>) : void;
-export function waterfall<T, E>(tasks: Function[], callback?: AsyncResultCallback<T, E | Error>): void;
+export function series<T, E = Error>(tasks: AsyncFunction<T, E>[], callback?: AsyncResultArrayCallback<T, E>): void;
+export function series<T, E = Error>(tasks: Dictionary<AsyncFunction<T, E>>, callback?: AsyncResultObjectCallback<T, E>): void;
+export function parallel<T, E = Error>(tasks: Array<AsyncFunction<T, E>>, callback?: AsyncResultArrayCallback<T, E>): void;
+export function parallel<T, E = Error>(tasks: Dictionary<AsyncFunction<T, E>>, callback?: AsyncResultObjectCallback<T, E>): void;
+export function parallelLimit<T, E = Error>(tasks: Array<AsyncFunction<T, E>>, limit: number, callback?: AsyncResultArrayCallback<T, E>): void;
+export function parallelLimit<T, E = Error>(tasks: Dictionary<AsyncFunction<T, E>>, limit: number, callback?: AsyncResultObjectCallback<T, E>): void;
+export function whilst<E = Error>(test: () => boolean, fn: AsyncVoidFunction<E>, callback: ErrorCallback<E>): void;
+export function doWhilst<T, E = Error>(fn: AsyncFunctionEx<T, E>, test: (...results: T[]) => boolean, callback: ErrorCallback<E>): void;
+export function until<E = Error>(test: () => boolean, fn: AsyncVoidFunction<E>, callback: ErrorCallback<E>): void;
+export function doUntil<T, E = Error>(fn: AsyncFunctionEx<T, E>, test: (...results: T[]) => boolean, callback: ErrorCallback<E>): void;
+export function during<E = Error>(test: (testCallback : AsyncBooleanResultCallback<E>) => void, fn: AsyncVoidFunction<E>, callback: ErrorCallback<E>): void;
+export function doDuring<E = Error>(fn: AsyncVoidFunction<E>, test: (testCallback: AsyncBooleanResultCallback<E>) => void, callback: ErrorCallback<E>): void;
+export function forever<E = Error>(next: (next : ErrorCallback<E>) => void, errBack: ErrorCallback<E>) : void;
+export function waterfall<T, E = Error>(tasks: Function[], callback?: AsyncResultCallback<T, E>): void;
 export function compose(...fns: Function[]): Function;
 export function seq(...fns: Function[]): Function;
 export function applyEach(fns: Function[], ...argsAndCallback: any[]): void;           // applyEach(fns, args..., callback). TS does not support ... for a middle argument. Callback is optional.
 export function applyEachSeries(fns: Function[], ...argsAndCallback: any[]): void;     // applyEachSeries(fns, args..., callback). TS does not support ... for a middle argument. Callback is optional.
-export function queue<T, E>(worker: AsyncWorker<T, E>, concurrency?: number): AsyncQueue<T>;
-export function queue<T, R, E>(worker: AsyncResultIterator<T, R, E>, concurrency?: number): AsyncQueue<T>;
-export function priorityQueue<T, E>(worker: AsyncWorker<T, E>, concurrency: number): AsyncPriorityQueue<T>;
-export function cargo<E>(worker : (tasks: any[], callback : ErrorCallback<E>) => void, payload? : number) : AsyncCargo;
-export function auto<R extends Dictionary<any>, E>(tasks: AsyncAutoTasks<R, E>, concurrency?: number, callback?: AsyncResultCallback<R, E>): void;
-export function autoInject<E>(tasks: any, callback?: AsyncResultCallback<any, E>): void;
-export function retry<T, E>(opts: number, task: (callback : AsyncResultCallback<T, E>, results: any) => void, callback:  AsyncResultCallback<any, E | Error>): void;
-export function retry<T, E>(opts: { times: number, interval: number|((retryCount: number) => number) }, task: (callback: AsyncResultCallback<T, E>, results : any) => void, callback:  AsyncResultCallback<any, E | Error>): void;
-export function retryable<T, E>(opts: number | {times: number, interval: number}, task: AsyncFunction<T, E>): AsyncFunction<T, E | Error>;
-export function apply<E>(fn: Function, ...args: any[]): AsyncFunction<any,E | Error>;
+export function queue<T, E = Error>(worker: AsyncWorker<T, E>, concurrency?: number): AsyncQueue<T>;
+export function queue<T, R, E = Error>(worker: AsyncResultIterator<T, R, E>, concurrency?: number): AsyncQueue<T>;
+export function priorityQueue<T, E = Error>(worker: AsyncWorker<T, E>, concurrency: number): AsyncPriorityQueue<T>;
+export function cargo<E = Error>(worker : (tasks: any[], callback : ErrorCallback<E>) => void, payload? : number) : AsyncCargo;
+export function auto<R extends Dictionary<any>, E = Error>(tasks: AsyncAutoTasks<R, E>, concurrency?: number, callback?: AsyncResultCallback<R, E>): void;
+export function auto<R extends Dictionary<any>, E = Error>(tasks: AsyncAutoTasks<R, E>, callback?: AsyncResultCallback<R, E>): void;
+export function autoInject<E = Error>(tasks: any, callback?: AsyncResultCallback<any, E>): void;
+export function retry<T, E = Error>(opts: number, task: (callback : AsyncResultCallback<T, E>, results: any) => void, callback:  AsyncResultCallback<any, E>): void;
+export function retry<T, E = Error>(opts: { times: number, interval: number|((retryCount: number) => number) }, task: (callback: AsyncResultCallback<T, E>, results : any) => void, callback:  AsyncResultCallback<any, E>): void;
+export function retryable<T, E = Error>(opts: number | {times: number, interval: number}, task: AsyncFunction<T, E>): AsyncFunction<T, E>;
+export function apply<E = Error>(fn: Function, ...args: any[]): AsyncFunction<any,E>;
 export function nextTick(callback: Function, ...args: any[]): void;
 export const setImmediate: typeof nextTick;
 
-export function reflect<T, E>(fn: AsyncFunction<T, E>) : (callback: (err: null, result: {error?: E, value?: T}) => void) => void;
-export function reflectAll<T, E>(tasks: AsyncFunction<T, E>[]): ((callback: (err: null, result: {error?: E, value?: T}) => void) => void)[];
+export function reflect<T, E = Error>(fn: AsyncFunction<T, E>) : (callback: (err: null, result: {error?: E, value?: T}) => void) => void;
+export function reflectAll<T, E = Error>(tasks: AsyncFunction<T, E>[]): ((callback: (err: null, result: {error?: E, value?: T}) => void) => void)[];
 
-export function timeout<T, E>(fn: AsyncFunction<T, E>, milliseconds: number, info?: any): AsyncFunction<T, E | Error>;
-export function timeout<T, R, E>(fn: AsyncResultIterator<T, R, E>, milliseconds: number, info?: any): AsyncResultIterator<T, R, E | Error>;
+export function timeout<T, E = Error>(fn: AsyncFunction<T, E>, milliseconds: number, info?: any): AsyncFunction<T, E>;
+export function timeout<T, R, E = Error>(fn: AsyncResultIterator<T, R, E>, milliseconds: number, info?: any): AsyncResultIterator<T, R, E>;
 
 export function times<T, E> (n: number, iterator: AsyncResultIterator<number, T, E>, callback: AsyncResultArrayCallback<T, E>): void;
-export function timesSeries<T, E>(n: number, iterator: AsyncResultIterator<number, T, E>, callback: AsyncResultArrayCallback<T, E>): void;
-export function timesLimit<T, E>(n: number, limit: number, iterator: AsyncResultIterator<number, T, E>, callback: AsyncResultArrayCallback<T, E>): void;
+export function timesSeries<T, E = Error>(n: number, iterator: AsyncResultIterator<number, T, E>, callback: AsyncResultArrayCallback<T, E>): void;
+export function timesLimit<T, E = Error>(n: number, limit: number, iterator: AsyncResultIterator<number, T, E>, callback: AsyncResultArrayCallback<T, E>): void;
 
-export function transform<T, R, E>(arr: T[], iteratee: (acc: R[], item: T, key: number, callback: (error?: E) => void) => void, callback?: AsyncResultArrayCallback<T, E>): void;
-export function transform<T, R, E>(arr: T[], acc: R[], iteratee: (acc: R[], item: T, key: number, callback: (error?: E) => void) => void, callback?: AsyncResultArrayCallback<T, E>): void;
+export function transform<T, R, E = Error>(arr: T[], iteratee: (acc: R[], item: T, key: number, callback: (error?: E) => void) => void, callback?: AsyncResultArrayCallback<T, E>): void;
+export function transform<T, R, E = Error>(arr: T[], acc: R[], iteratee: (acc: R[], item: T, key: number, callback: (error?: E) => void) => void, callback?: AsyncResultArrayCallback<T, E>): void;
 
-export function transform<T, R, E>(arr: {[key: string] : T}, iteratee: (acc: {[key: string] : R}, item: T, key: string, callback: (error?: E) => void) => void, callback?: AsyncResultObjectCallback<T, E>): void;
-export function transform<T, R, E>(arr: {[key: string] : T}, acc: {[key: string] : R}, iteratee: (acc: {[key: string] : R}, item: T, key: string, callback: (error?: E) => void) => void, callback?: AsyncResultObjectCallback<T, E>): void;
+export function transform<T, R, E = Error>(arr: {[key: string] : T}, iteratee: (acc: {[key: string] : R}, item: T, key: string, callback: (error?: E) => void) => void, callback?: AsyncResultObjectCallback<T, E>): void;
+export function transform<T, R, E = Error>(arr: {[key: string] : T}, acc: {[key: string] : R}, iteratee: (acc: {[key: string] : R}, item: T, key: string, callback: (error?: E) => void) => void, callback?: AsyncResultObjectCallback<T, E>): void;
 
-export function race<T, E>(tasks: (AsyncFunction<T, E>)[], callback: AsyncResultCallback<T, E | Error>) : void;
+export function race<T, E = Error>(tasks: (AsyncFunction<T, E>)[], callback: AsyncResultCallback<T, E>) : void;
 
 // Utils
 export function memoize(fn: Function, hasher?: Function): Function;
diff --git a/types/async/test/index.ts b/types/async/test/index.ts
index 3c6c2f5dfe..0081dd3dcd 100644
--- a/types/async/test/index.ts
+++ b/types/async/test/index.ts
@@ -114,7 +114,7 @@ async.series([
 ],
 function (err, results) { });
 
-async.series<string,Error>([
+async.series<string>([
     function (callback) {
         callback(undefined, 'one');
     },
@@ -138,7 +138,7 @@ async.series({
 },
 function (err, results) { });
 
-async.series<number,Error>({
+async.series<number>({
     one: function (callback) {
         setTimeout(function () {
             callback(undefined, 1);
@@ -178,7 +178,7 @@ async.parallel([
 ],
 function (err, results) { });
 
-async.parallel<string,Error>([
+async.parallel<string>([
     function (callback) {
         setTimeout(function () {
             callback(undefined, 'one');
@@ -207,7 +207,7 @@ async.parallel({
 },
 function (err, results) { });
 
-async.parallel<number,Error>({
+async.parallel<number>({
     one: function (callback) {
         setTimeout(function () {
             callback(undefined, 1);
@@ -273,7 +273,7 @@ async.waterfall([
 ], function (err, result) { });
 
 
-var q = async.queue<any,Error>(function (task: any, callback: (err?:Error,msg?:string) => void) {
+var q = async.queue<any>(function (task: any, callback: (err?:Error,msg?:string) => void) {
     console.log('hello ' + task.name);
     callback(undefined,'a message.');
 }, 2);
@@ -293,7 +293,7 @@ q.push([{ name: 'baz' }, { name: 'bay' }, { name: 'bax' }], function (err) {
     console.log('finished processing bar');
 });
 
-q.push<string,Error>({name: 'foo'}, function (err,msg) {
+q.push<string>({name: 'foo'}, function (err, msg) {
   console.log('foo finished with a message "'+ msg! + '"');
 });
 
@@ -330,7 +330,7 @@ q.resume();
 q.kill();
 
 // tests for strongly typed tasks
-var q2 = async.queue<string,Error>(function (task: string, callback: () => void) {
+var q2 = async.queue<string>(function (task: string, callback: () => void) {
     console.log('Task: ' + task);
     callback();
 }, 1);
@@ -356,7 +356,7 @@ q2.unshift(['task3', 'task4', 'task5'], function (error) {
 });
 
 
-var aq = async.queue<number, number, Error>(function (level: number, callback: (error?: Error, newLevel?: number) => void) {
+var aq = async.queue<number, number>(function (level: number, callback: (error?: Error, newLevel?: number) => void) {
     console.log('hello ' + level);
     callback(undefined, level+1);
 });
@@ -387,14 +387,47 @@ cargo.push({ name: 'baz' }, function (err: Error) {
 
 var filename = '';
 async.auto({
-    get_data: function (callback: any) { },
-    make_folder: function (callback: any) { },
+    get_data: function (callback: AsyncResultCallback<any>) { },
+    make_folder: function (callback: AsyncResultCallback<any>) { },
     //arrays with different types are not accepted by TypeScript.
-    write_file: ['get_data', 'make_folder', <any>function (callback: any) {
+    write_file: ['get_data', 'make_folder', <any>function (callback: AsyncResultCallback<any>) {
         callback(null, filename);
     }],
     //arrays with different types are not accepted by TypeScript.
-    email_link: ['write_file', <any>function (callback: any, results: any) { }]
+    email_link: ['write_file', <any>function (callback: AsyncResultCallback<any>, results: any) { }]
+});
+
+async.auto({
+    get_data: function (callback: AsyncResultCallback<any>) { },
+    make_folder: function (callback: AsyncResultCallback<any>) { },
+    //arrays with different types are not accepted by TypeScript.
+    write_file: ['get_data', 'make_folder', <any>function (callback: AsyncResultCallback<any>) {
+        callback(null, filename);
+    }],
+    //arrays with different types are not accepted by TypeScript.
+    email_link: ['write_file', <any>function (callback: AsyncResultCallback<any>, results: any) { }]
+}, function (err, results) {
+    console.log('finished auto');
+});
+
+interface A {
+    get_data: any;
+    make_folder: any;
+    write_file: any;
+    email_link: any;
+}
+
+async.auto<A>({
+    get_data: function (callback: AsyncResultCallback<any>) { },
+    make_folder: function (callback: AsyncResultCallback<any>) { },
+    //arrays with different types are not accepted by TypeScript.
+    write_file: ['get_data', 'make_folder', <any>function (callback: AsyncResultCallback<any>) {
+        callback(null, filename);
+    }],
+    //arrays with different types are not accepted by TypeScript.
+    email_link: ['write_file', <any>function (callback: AsyncResultCallback<any>, results: any) { }]
+}, 1, function (err, results) {
+    console.log('finished auto');
 });
 
 async.retry(3, function (callback, results) { }, function (err, result) { });
@@ -459,10 +492,10 @@ async.dir(function (name: string, callback: any) {
 
 // each
 
-async.each<number,Error>({
+async.each<number>({
     "a": 1,
     "b": 2
-}, function(val: number, next: ErrorCallback<Error>): void {
+}, function(val: number, next: ErrorCallback): void {
 
     setTimeout(function(): void {
 
@@ -478,10 +511,10 @@ async.each<number,Error>({
 
 });
 
-async.eachSeries<number, Error>({
+async.eachSeries<number>({
     "a": 1,
     "b": 2
-}, function(val: number, next: ErrorCallback<Error>): void {
+}, function(val: number, next: ErrorCallback): void {
 
     setTimeout(function(): void {
 
@@ -497,14 +530,14 @@ async.eachSeries<number, Error>({
 
 });
 
-async.eachLimit<number, Error>({
+async.eachLimit<number>({
     "a": 1,
     "b": 2,
     "c": 3,
     "d": 4,
     "e": 5,
     "f": 6
-}, 2, function(val: number, next: ErrorCallback<Error>): void {
+}, 2, function(val: number, next: ErrorCallback): void {
 
     setTimeout(function(): void {
 
@@ -522,10 +555,10 @@ async.eachLimit<number, Error>({
 
 // forEachOf/eachOf
 
-async.eachOf<number, Error>({
+async.eachOf<number>({
     "a": 1,
     "b": 2
-}, function(val: number, key: string, next: ErrorCallback<Error>): void {
+}, function(val: number, key: string, next: ErrorCallback): void {
 
     setTimeout(function(): void {
 
@@ -541,10 +574,10 @@ async.eachOf<number, Error>({
 
 });
 
-async.forEachOfSeries<number, Error>({
+async.forEachOfSeries<number>({
     "a": 1,
     "b": 2
-}, function(val: number, key: string, next: ErrorCallback<Error>): void {
+}, function(val: number, key: string, next: ErrorCallback): void {
 
     setTimeout(function(): void {
 
@@ -560,14 +593,14 @@ async.forEachOfSeries<number, Error>({
 
 });
 
-async.forEachOfLimit<number, Error>({
+async.forEachOfLimit<number>({
     "a": 1,
     "b": 2,
     "c": 3,
     "d": 4,
     "e": 5,
     "f": 6
-}, 2, function(val: number, key: string, next: ErrorCallback<Error>): void {
+}, 2, function(val: number, key: string, next: ErrorCallback): void {
 
     setTimeout(function(): void {
 
@@ -585,11 +618,11 @@ async.forEachOfLimit<number, Error>({
 
 // map
 
-async.map<number, string, Error>({
+async.map<number, string>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(val: number, next: AsyncResultCallback<string, Error>): void {
+}, function(val: number, next: AsyncResultCallback<string>): void {
 
     setTimeout(function(): void {
 
@@ -605,11 +638,11 @@ async.map<number, string, Error>({
 
 });
 
-async.mapSeries<number, string, Error>({
+async.mapSeries<number, string>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(val: number, next: AsyncResultCallback<string, Error>): void {
+}, function(val: number, next: AsyncResultCallback<string>): void {
 
     setTimeout(function(): void {
 
@@ -625,14 +658,14 @@ async.mapSeries<number, string, Error>({
 
 });
 
-async.mapLimit<number, string, Error>({
+async.mapLimit<number, string>({
     "a": 1,
     "b": 2,
     "c": 3,
     "d": 4,
     "e": 5,
     "f": 6
-}, 2, function(val: number, next: AsyncResultCallback<string, Error>): void {
+}, 2, function(val: number, next: AsyncResultCallback<string>): void {
 
     setTimeout(function(): void {
 
@@ -650,11 +683,11 @@ async.mapLimit<number, string, Error>({
 
 // mapValues
 
-async.mapValues<number, string, Error>({
+async.mapValues<number, string>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(val: number, key: string, next: AsyncResultCallback<string, Error>): void {
+}, function(val: number, key: string, next: AsyncResultCallback<string>): void {
 
     setTimeout(function(): void {
 
@@ -670,11 +703,11 @@ async.mapValues<number, string, Error>({
 
 });
 
-async.mapValuesSeries<number, string, Error>({
+async.mapValuesSeries<number, string>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(val: number, key: string, next: AsyncResultCallback<string, Error>): void {
+}, function(val: number, key: string, next: AsyncResultCallback<string>): void {
 
     setTimeout(function(): void {
 
@@ -692,11 +725,11 @@ async.mapValuesSeries<number, string, Error>({
 
 // filter/select/reject
 
-async.filter<number, Error>({
+async.filter<number>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(val: number, next: AsyncBooleanResultCallback<Error>): void {
+}, function(val: number, next: AsyncBooleanResultCallback): void {
 
     setTimeout(function(): void {
 
@@ -712,11 +745,11 @@ async.filter<number, Error>({
 
 });
 
-async.reject<number, Error>({
+async.reject<number>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(val: number, next: AsyncBooleanResultCallback<Error>): void {
+}, function(val: number, next: AsyncBooleanResultCallback): void {
 
     setTimeout(function(): void {
 
@@ -734,11 +767,11 @@ async.reject<number, Error>({
 
 // concat
 
-async.concat<string, string, Error>({
+async.concat<string, string>({
     "a": "1",
     "b": "2",
     "c": "3"
-}, function(item: string, next: AsyncResultCallback<string[], Error>): void {
+}, function(item: string, next: AsyncResultCallback<string[]>): void {
 
     console.log(`async.concat: ${item}`);
 
@@ -752,11 +785,11 @@ async.concat<string, string, Error>({
 
 // detect/find
 
-async.detect<number, Error>({
+async.detect<number>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(item: number, next: AsyncBooleanResultCallback<Error>): void {
+}, function(item: number, next: AsyncBooleanResultCallback): void {
 
     console.log(`async.detect/find: ${item}`);
 
@@ -777,11 +810,11 @@ async.detect<number, Error>({
 
 // every/all
 
-async.every<number,Error>({
+async.every<number>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(item: number, next: AsyncBooleanResultCallback<Error>): void {
+}, function(item: number, next: AsyncBooleanResultCallback): void {
 
     console.log(`async.every/all: ${item}`);
 
@@ -795,11 +828,11 @@ async.every<number,Error>({
 
 // some/any
 
-async.some<number, Error>({
+async.some<number>({
     "a": 1,
     "b": 2,
     "c": 3
-}, function(item: number, next: AsyncBooleanResultCallback<Error>): void {
+}, function(item: number, next: AsyncBooleanResultCallback): void {
 
     console.log(`async.some/any: ${item}`);
 
diff --git a/types/i2c-bus/index.d.ts b/types/i2c-bus/index.d.ts
index ebb06e83ae..188210653a 100644
--- a/types/i2c-bus/index.d.ts
+++ b/types/i2c-bus/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/fivdi/i2c-bus
 // Definitions by: Jason Heard <https://github.com/101100>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.1
+// TypeScript Version: 2.3
 
 /// <reference types="node" />
 
diff --git a/types/libpq/index.d.ts b/types/libpq/index.d.ts
index 2897eb3aab..09c358d6a6 100644
--- a/types/libpq/index.d.ts
+++ b/types/libpq/index.d.ts
@@ -2,7 +2,7 @@
 // Project: https://github.com/brianc/node-libpq#readme
 // Definitions by: Vlad Rindevich <https://github.com/Lodin>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-// TypeScript Version: 2.2
+// TypeScript Version: 2.3
 
 /// <reference types="node" />