diff --git a/README.md b/README.md
index 280f9d5..83bd9da 100644
--- a/README.md
+++ b/README.md
@@ -134,5 +134,8 @@ The options used to create a pool cluster. See [mysqljs/mysql documentation](htt
 
 `poolCluster.on`: Add a listener to the pool cluster object. See [mysqljs/mysql documentation](https://github.com/mysqljs/mysql#poolcluster) for events that may be listened for.
 
-## Upgrading from v3
+## Upgrading from v3 to v4
 The main difference is that `mysql.createPool` now returns a promise. Besides this, the API is the same and you should be able to upgrade straight to v4. The only other difference is the extra options in the [connectionOptions object](#connectionoptions-object).
+
+## Upgrading from v4 to v5
+The `pool.releaseConnection` has been removed, please use `poolConnection.release` instead.
diff --git a/lib/pool.js b/lib/pool.js
index bbd3e81..3350963 100644
--- a/lib/pool.js
+++ b/lib/pool.js
@@ -53,11 +53,6 @@ class pool {
             });
     }
 
-    releaseConnection(connection) {
-        //Use the underlying connection from the mysql-module here:
-        return this.pool.releaseConnection(connection.connection);
-    }
-
     query() {
         return promiseCallback.apply(this.pool, ['query', arguments, this.returnArgumentsArray]);
     }
diff --git a/package-lock.json b/package-lock.json
index 6f8c93a..7cb5278 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "promise-mysql",
-  "version": "4.1.4",
+  "version": "5.0.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index 08490a6..0891d53 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "promise-mysql",
-  "version": "4.1.4",
+  "version": "5.0.0",
   "description": "A bluebird wrapper for node-mysql",
   "main": "index.js",
   "scripts": {
diff --git a/test/pool.js b/test/pool.js
index 41c00a7..77f9f5f 100644
--- a/test/pool.js
+++ b/test/pool.js
@@ -11,7 +11,6 @@ sinon.addBehavior(`callsLastArgWith`, (fake, errVal, retVal) => {
 
 const poolMock = {
     getConnection: sinon.stub().callsLastArgWith(null, `getConnectionPromise`).returns(`getConnectionReturn`),
-    releaseConnection: sinon.stub().returns(`releaseConnectionReturn`),
     query: sinon.stub().callsLastArgWith(null, `queryPromise`).returns(`queryReturn`),
     end: sinon.stub().callsLastArgWith(null, `endPromise`).returns(`endReturn`),
     escape: sinon.stub().returnsArg(0),
@@ -36,7 +35,6 @@ const pool = proxyquire(`../lib/pool.js`, {
 tap.beforeEach((done) => {
     createPool.resetHistory();
     poolMock.getConnection.resetHistory();
-    poolMock.releaseConnection.resetHistory();
     poolMock.query.resetHistory();
     poolMock.end.resetHistory();
     poolMock.escape.resetHistory();
@@ -230,30 +228,6 @@ tap.test(`calls the underlying methods`, (t) => {
             });
         });
 
-        t.test(`pool.releaseConnection should call the underlying releaseConnection method with the correct arguments`, (t) => {
-            const connection = {
-                connection: 'test'
-            }
-
-            const retVal = pool.releaseConnection(connection)
-
-            t.ok(poolMock.releaseConnection.calledOnce, `underlying releaseConnection method called`)
-            t.equal(
-                poolMock.releaseConnection.lastCall.args.length,
-                1,
-                `underlying releaseConnection called with correct number of arguments`
-            );
-            t.ok(poolMock.releaseConnection.calledWith(connection.connection));
-
-            t.same(
-                retVal,
-                `releaseConnectionReturn`,
-                `returns arguments`
-            );
-
-            t.end();
-        });
-
         t.end();
     });
 })