diff --git a/.eslintrc b/.eslintrc
index c4f8674..d34b21e 100644
--- a/.eslintrc
+++ b/.eslintrc
@@ -4,6 +4,7 @@
     "comma-dangle": ["error", {
       "functions": "ignore"
     }],
+    "no-confusing-arrow": 0,
     "no-underscore-dangle": [
       "error",
       { "allowAfterThis": true }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2752c66..9971c3b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+
+## [6.3.3] - 2025-05-01
+
+### Fixed
+- Added backward compatibility with v5's compare function format for MinPriorityQueue and MaxPriorityQueue
+- Fixed iterator type.
+
 ## [6.3.2] - 2025-01-05
 
 ### Fixed
diff --git a/README.md b/README.md
index 4bb6e3c..4b1b185 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ A heap-based implementation of priority queue in javascript with typescript supp
 <img src="https://user-images.githubusercontent.com/6517308/121813242-859a9700-cc6b-11eb-99c0-49e5bb63005b.jpg">
 
 
-# Contents (v6)
+# Contents
 * [Install](#install)
 * [require](#require)
 * [import](#import)
@@ -123,6 +123,19 @@ const numbersQueue = new MinPriorityQueue();
 const bidsQueue = new MaxPriorityQueue((bid) => bid.value);
 ```
 
+##### Legacy Compare Function (v5 compatibility)
+For backward compatibility with v5, you can also pass a compare function in an options object:
+
+```js
+// MinPriorityQueue with legacy compare
+const minQueue = new MinPriorityQueue({ compare: (a, b) => a - b });
+
+// MaxPriorityQueue with legacy compare
+const maxQueue = new MaxPriorityQueue({ compare: (a, b) => a - b });
+```
+
+This format is supported for backward compatibility with v5 of the library.
+
 ### fromArray
 If the queue is being created from an existing array, and there is no desire to use an extra O(n) space, this static function can turn an array into a priority queue in O(n) runtime.
 
diff --git a/index.d.ts b/index.d.ts
index e194f2d..fd211b0 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -1,5 +1,5 @@
 import { PriorityQueue } from './src/priorityQueue';
-import { MinPriorityQueue } from './src/minPriorityQueue';
+import { MinPriorityQueue, LegacyOptions } from './src/minPriorityQueue';
 import { MaxPriorityQueue } from './src/maxPriorityQueue';
 import { ICompare, IGetCompareValue } from '@datastructures-js/heap';
 
@@ -8,3 +8,4 @@ export { MinPriorityQueue }
 export { MaxPriorityQueue }
 export { ICompare }
 export { IGetCompareValue }
+export { LegacyOptions }
diff --git a/package.json b/package.json
index 956f55d..a64d4d4 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@datastructures-js/priority-queue",
-  "version": "6.3.2",
+  "version": "6.3.3",
   "description": "A heap-based implementation of priority queue in javascript with typescript support.",
   "main": "index.js",
   "types": "index.d.ts",
diff --git a/src/maxPriorityQueue.d.ts b/src/maxPriorityQueue.d.ts
index fd8db9c..8a8eae1 100644
--- a/src/maxPriorityQueue.d.ts
+++ b/src/maxPriorityQueue.d.ts
@@ -1,7 +1,8 @@
 import { MaxHeap, IGetCompareValue } from '@datastructures-js/heap';
+import { LegacyOptions } from './minPriorityQueue';
 
 export class MaxPriorityQueue<T> implements Iterable<T> {
-  constructor(getCompareValue?: IGetCompareValue<T>, heap?: MaxHeap<T>);
+  constructor(options?: IGetCompareValue<T> | LegacyOptions<T>, heap?: MaxHeap<T>);
   [Symbol.iterator](): Iterator<T, any, undefined>;
   size(): number;
   isEmpty(): boolean;
diff --git a/src/maxPriorityQueue.js b/src/maxPriorityQueue.js
index 1e64a8a..25471ff 100644
--- a/src/maxPriorityQueue.js
+++ b/src/maxPriorityQueue.js
@@ -13,14 +13,22 @@ const getMaxCompare = (getCompareValue) => (a, b) => {
 
 /**
  * @class MaxPriorityQueue
- * @extends MaxHeap
  */
 class MaxPriorityQueue {
-  constructor(getCompareValue, _heap) {
-    if (getCompareValue && typeof getCompareValue !== 'function') {
-      throw new Error('MaxPriorityQueue constructor requires a callback for object values');
+  constructor(options, _heap) {
+    // Handle legacy options format ({ compare: fn })
+    if (options && typeof options === 'object' && typeof options.compare === 'function') {
+      this._getCompareValue = null;
+      const compareFunction = (a, b) => options.compare(a, b) >= 0 ? -1 : 1;
+      this._heap = _heap || new Heap(compareFunction);
+    } else {
+      // Current format (direct compare function)
+      const getCompareValue = options;
+      if (getCompareValue && typeof getCompareValue !== 'function') {
+        throw new Error('MaxPriorityQueue constructor requires a callback for object values');
+      }
+      this._heap = _heap || new MaxHeap(getCompareValue);
     }
-    this._heap = _heap || new MaxHeap(getCompareValue);
   }
 
   /**
diff --git a/src/minPriorityQueue.d.ts b/src/minPriorityQueue.d.ts
index 8f52bf9..ed6fc45 100644
--- a/src/minPriorityQueue.d.ts
+++ b/src/minPriorityQueue.d.ts
@@ -1,7 +1,11 @@
 import { MinHeap, IGetCompareValue } from '@datastructures-js/heap';
 
+export interface LegacyOptions<T> {
+  compare: (a: T, b: T) => number;
+}
+
 export class MinPriorityQueue<T> implements Iterable<T> {
-  constructor(getCompareValue?: IGetCompareValue<T>, heap?: MinHeap<T>);
+  constructor(options?: IGetCompareValue<T> | LegacyOptions<T>, heap?: MinHeap<T>);
   [Symbol.iterator](): Iterator<T, any, undefined>;
   size(): number;
   isEmpty(): boolean;
diff --git a/src/minPriorityQueue.js b/src/minPriorityQueue.js
index 1da0e99..116657c 100644
--- a/src/minPriorityQueue.js
+++ b/src/minPriorityQueue.js
@@ -15,11 +15,20 @@ const getMinCompare = (getCompareValue) => (a, b) => {
  * @class MinPriorityQueue
  */
 class MinPriorityQueue {
-  constructor(getCompareValue, _heap) {
-    if (getCompareValue && typeof getCompareValue !== 'function') {
-      throw new Error('MinPriorityQueue constructor requires a callback for object values');
+  constructor(options, _heap) {
+    // Handle legacy options format ({ compare: fn })
+    if (options && typeof options === 'object' && typeof options.compare === 'function') {
+      this._getCompareValue = null;
+      const compareFunction = (a, b) => options.compare(a, b) <= 0 ? -1 : 1;
+      this._heap = _heap || new Heap(compareFunction);
+    } else {
+      // Current format (direct compare function)
+      const getCompareValue = options;
+      if (getCompareValue && typeof getCompareValue !== 'function') {
+        throw new Error('MinPriorityQueue constructor requires a callback for object values');
+      }
+      this._heap = _heap || new MinHeap(getCompareValue);
     }
-    this._heap = _heap || new MinHeap(getCompareValue);
   }
 
   /**
diff --git a/test/maxPriorityQueue.test.js b/test/maxPriorityQueue.test.js
index 0ce101d..bd1d711 100644
--- a/test/maxPriorityQueue.test.js
+++ b/test/maxPriorityQueue.test.js
@@ -128,4 +128,20 @@ describe('MaxPriorityQueue', () => {
       });
     });
   });
+
+  describe('legacy compare function', () => {
+    const values = [50, 80, 30, 90, 60, 40, 20];
+    const maxQ = new MaxPriorityQueue({ compare: (a, b) => a - b });
+
+    it('enqueue and dequeue with legacy compare', () => {
+      values.forEach((value) => maxQ.enqueue(value));
+      expect(maxQ.dequeue()).to.equal(90);
+      expect(maxQ.dequeue()).to.equal(80);
+      expect(maxQ.dequeue()).to.equal(60);
+      expect(maxQ.dequeue()).to.equal(50);
+      expect(maxQ.dequeue()).to.equal(40);
+      expect(maxQ.dequeue()).to.equal(30);
+      expect(maxQ.dequeue()).to.equal(20);
+    });
+  });
 });
diff --git a/test/minPriorityQueue.test.js b/test/minPriorityQueue.test.js
index 78b6b00..e4af573 100644
--- a/test/minPriorityQueue.test.js
+++ b/test/minPriorityQueue.test.js
@@ -125,4 +125,20 @@ describe('MinPriorityQueue', () => {
     });
 
   });
+
+  describe('legacy compare function', () => {
+    const values = [50, 80, 30, 90, 60, 40, 20];
+    const minQ = new MinPriorityQueue({ compare: (a, b) => a - b });
+
+    it('enqueue and dequeue with legacy compare', () => {
+      values.forEach((value) => minQ.enqueue(value));
+      expect(minQ.dequeue()).to.equal(20);
+      expect(minQ.dequeue()).to.equal(30);
+      expect(minQ.dequeue()).to.equal(40);
+      expect(minQ.dequeue()).to.equal(50);
+      expect(minQ.dequeue()).to.equal(60);
+      expect(minQ.dequeue()).to.equal(80);
+      expect(minQ.dequeue()).to.equal(90);
+    });
+  });
 });