diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index 14799c6464a..a9b09e2962d 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -3274,10 +3274,7 @@ $wgResourceModuleSkinStyles = array();
  *
  * @par Example:
  * @code
- *   $wgResourceLoaderSources['foo'] = array(
- *       'loadScript' => 'http://example.org/w/load.php',
- *       'apiScript' => 'http://example.org/w/api.php'
- *   );
+ *   $wgResourceLoaderSources['foo'] = 'http://example.org/w/load.php';
  * @endcode
  */
 $wgResourceLoaderSources = array();
diff --git a/includes/resourceloader/ResourceLoader.php b/includes/resourceloader/ResourceLoader.php
index 5f72d8d2f4e..a356e2e3b3c 100644
--- a/includes/resourceloader/ResourceLoader.php
+++ b/includes/resourceloader/ResourceLoader.php
@@ -32,9 +32,6 @@ class ResourceLoader {
 	/** @var int */
 	protected static $filterCacheVersion = 7;
 
-	/** @var array */
-	protected static $requiredSourceProperties = array( 'loadScript' );
-
 	/** @var bool */
 	protected static $debugMode = null;
 
@@ -53,7 +50,7 @@ class ResourceLoader {
 	 */
 	protected $testModuleNames = array();
 
-	/** @var array E.g. array( 'source-id' => array( 'loadScript' => 'http://.../load.php' ) ) */
+	/** @var array E.g. array( 'source-id' => 'http://.../load.php' ) */
 	protected $sources = array();
 
 	/** @var bool */
@@ -231,10 +228,7 @@ class ResourceLoader {
 		$this->config = $config;
 
 		// Add 'local' source first
-		$this->addSource(
-			'local',
-			array( 'loadScript' => wfScript( 'load' ), 'apiScript' => wfScript( 'api' ) )
-		);
+		$this->addSource( 'local', wfScript( 'load' ) );
 
 		// Add other sources
 		$this->addSource( $config->get( 'ResourceLoaderSources' ) );
@@ -401,14 +395,12 @@ class ResourceLoader {
 	/**
 	 * Add a foreign source of modules.
 	 *
-	 * Source properties:
-	 * 'loadScript': URL (either fully-qualified or protocol-relative) of load.php for this source
-	 *
-	 * @param mixed $id Source ID (string), or array( id1 => props1, id2 => props2, ... )
-	 * @param array $properties Source properties
+	 * @param array|string $id Source ID (string), or array( id1 => loadUrl, id2 => loadUrl, ... )
+	 * @param string|array $loadUrl load.php url (string), or array with loadUrl key for
+	 *  backwards-compatability.
 	 * @throws MWException
 	 */
-	public function addSource( $id, $properties = null ) {
+	public function addSource( $id, $loadUrl = null ) {
 		// Allow multiple sources to be registered in one call
 		if ( is_array( $id ) ) {
 			foreach ( $id as $key => $value ) {
@@ -425,14 +417,18 @@ class ResourceLoader {
 			);
 		}
 
-		// Validate properties
-		foreach ( self::$requiredSourceProperties as $prop ) {
-			if ( !isset( $properties[$prop] ) ) {
-				throw new MWException( "Required property $prop missing from source ID $id" );
+		// Pre 1.24 backwards-compatability
+		if ( is_array( $loadUrl ) ) {
+			if ( !isset( $loadUrl['loadScript'] ) ) {
+				throw new MWException(
+					__METHOD__ . ' was passed an array with no "loadScript" key.'
+				);
 			}
+
+			$loadUrl = $loadUrl['loadScript'];
 		}
 
-		$this->sources[$id] = $properties;
+		$this->sources[$id] = $loadUrl;
 	}
 
 	/**
@@ -527,7 +523,7 @@ class ResourceLoader {
 	/**
 	 * Get the list of sources.
 	 *
-	 * @return array Like array( id => array of properties, .. )
+	 * @return array Like array( id => load.php url, .. )
 	 */
 	public function getSources() {
 		return $this->sources;
@@ -546,7 +542,7 @@ class ResourceLoader {
 		if ( !isset( $this->sources[$source] ) ) {
 			throw new MWException( "The $source source was never registered in ResourceLoader." );
 		}
-		return $this->sources[$source]['loadScript'];
+		return $this->sources[$source];
 	}
 
 	/**
@@ -1228,7 +1224,7 @@ class ResourceLoader {
 	 *   - ResourceLoader::makeLoaderSourcesScript( $id, $properties ):
 	 *       Register a single source
 	 *
-	 *   - ResourceLoader::makeLoaderSourcesScript( array( $id1 => $props1, $id2 => $props2, ... ) );
+	 *   - ResourceLoader::makeLoaderSourcesScript( array( $id1 => $loadUrl, $id2 => $loadUrl, ... ) );
 	 *       Register sources with the given IDs and properties.
 	 *
 	 * @param string $id Source ID
diff --git a/resources/src/mediawiki/mediawiki.js b/resources/src/mediawiki/mediawiki.js
index d50fe48f94f..0d57d59bb4e 100644
--- a/resources/src/mediawiki/mediawiki.js
+++ b/resources/src/mediawiki/mediawiki.js
@@ -628,12 +628,10 @@
 			 */
 			var registry = {},
 				//
-				// Mapping of sources, keyed by source-id, values are objects.
+				// Mapping of sources, keyed by source-id, values are strings.
 				// Format:
 				//	{
-				//		'sourceId': {
-				//			'loadScript': 'http://foo.bar/w/load.php'
-				//		}
+				//		'sourceId': 'http://foo.bar/w/load.php'
 				//	}
 				//
 				sources = {},
@@ -1478,7 +1476,7 @@
 
 					for ( source in splits ) {
 
-						sourceLoadScript = sources[source].loadScript;
+						sourceLoadScript = sources[source];
 
 						for ( group in splits[source] ) {
 
@@ -1552,15 +1550,14 @@
 				 *
 				 * The #work method will use this information to split up requests by source.
 				 *
-				 *     mw.loader.addSource( 'mediawikiwiki', { loadScript: '//www.mediawiki.org/w/load.php' } );
+				 *     mw.loader.addSource( 'mediawikiwiki', '//www.mediawiki.org/w/load.php' );
 				 *
 				 * @param {string} id Short string representing a source wiki, used internally for
 				 *  registered modules to indicate where they should be loaded from (usually lowercase a-z).
-				 * @param {Object} props
-				 * @param {string} props.loadScript Url to the load.php entry point of the source wiki.
+				 * @param {Object|string} loadUrl load.php url, may be an object for backwards-compatability
 				 * @return {boolean}
 				 */
-				addSource: function ( id, props ) {
+				addSource: function ( id, loadUrl ) {
 					var source;
 					// Allow multiple additions
 					if ( typeof id === 'object' ) {
@@ -1574,7 +1571,11 @@
 						throw new Error( 'source already registered: ' + id );
 					}
 
-					sources[id] = props;
+					if ( typeof loadUrl === 'object' ) {
+						loadUrl = loadUrl.loadScript;
+					}
+
+					sources[id] = loadUrl;
 
 					return true;
 				},
diff --git a/tests/phpunit/includes/resourceloader/ResourceLoaderStartupModuleTest.php b/tests/phpunit/includes/resourceloader/ResourceLoaderStartupModuleTest.php
index 0c250bd7620..a1893873280 100644
--- a/tests/phpunit/includes/resourceloader/ResourceLoaderStartupModuleTest.php
+++ b/tests/phpunit/includes/resourceloader/ResourceLoaderStartupModuleTest.php
@@ -9,10 +9,7 @@ class ResourceLoaderStartupModuleTest extends ResourceLoaderTestCase {
 				'modules' => array(),
 				'out' => '
 mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    }
+    "local": "/w/load.php"
 } );mw.loader.register( [] );'
 			) ),
 			array( array(
@@ -22,10 +19,7 @@ mw.loader.addSource( {
 				),
 				'out' => '
 mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    }
+    "local": "/w/load.php"
 } );mw.loader.register( [
     [
         "test.blank",
@@ -42,10 +36,7 @@ mw.loader.addSource( {
 				),
 				'out' => '
 mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    }
+    "local": "/w/load.php"
 } );mw.loader.register( [
     [
         "test.blank",
@@ -73,10 +64,7 @@ mw.loader.addSource( {
 				),
 				'out' => '
 mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    }
+    "local": "/w/load.php"
 } );mw.loader.register( [
     [
         "test.blank",
@@ -97,14 +85,8 @@ mw.loader.addSource( {
 				),
 				'out' => '
 mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    },
-    "example": {
-        "loadScript": "http://example.org/w/load.php",
-        "apiScript": "http://example.org/w/api.php"
-    }
+    "local": "/w/load.php",
+    "example": "http://example.org/w/load.php"
 } );mw.loader.register( [
     [
         "test.blank",
@@ -140,10 +122,7 @@ mw.loader.addSource( {
 				),
 				'out' => '
 mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    }
+    "local": "/w/load.php"
 } );mw.loader.register( [
     [
         "test.x.core",
@@ -238,14 +217,8 @@ mw.loader.addSource( {
 				),
 				'out' => '
 mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    },
-    "example": {
-        "loadScript": "http://example.org/w/load.php",
-        "apiScript": "http://example.org/w/api.php"
-    }
+    "local": "/w/load.php",
+    "example": "http://example.org/w/load.php"
 } );mw.loader.register( [
     [
         "test.blank",
@@ -369,7 +342,7 @@ mw.loader.addSource( {
 		$rl->register( $modules );
 		$module = new ResourceLoaderStartUpModule();
 		$this->assertEquals(
-'mw.loader.addSource({"local":{"loadScript":"/w/load.php","apiScript":"/w/api.php"}});'
+'mw.loader.addSource({"local":"/w/load.php"});'
 . 'mw.loader.register(['
 . '["test.blank","1388534400"],'
 . '["test.min","1388534400",["test.blank"],null,"local",'
@@ -390,10 +363,7 @@ mw.loader.addSource( {
 		$module = new ResourceLoaderStartUpModule();
 		$this->assertEquals(
 'mw.loader.addSource( {
-    "local": {
-        "loadScript": "/w/load.php",
-        "apiScript": "/w/api.php"
-    }
+    "local": "/w/load.php"
 } );mw.loader.register( [
     [
         "test.blank",
diff --git a/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php b/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php
index bd6b3f23292..81a3dc4b6fc 100644
--- a/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php
+++ b/tests/phpunit/includes/resourceloader/ResourceLoaderTest.php
@@ -131,6 +131,43 @@ class ResourceLoaderTest extends ResourceLoaderTestCase {
 		);
 	}
 
+	public static function provideAddSource() {
+		return array(
+			array( 'examplewiki', '//example.org/w/load.php', 'examplewiki' ),
+			array( 'example2wiki', array( 'loadScript' => '//example.com/w/load.php' ), 'example2wiki' ),
+			array(
+				array( 'foowiki' => '//foo.org/w/load.php', 'bazwiki' => '//baz.org/w/load.php' ),
+				null,
+				array( 'foowiki', 'bazwiki' )
+			),
+			array(
+				array( 'foowiki' => '//foo.org/w/load.php' ),
+				null,
+				false,
+			),
+		);
+	}
+
+	/**
+	 * @dataProvider provideAddSource
+	 * @covers ResourceLoader::addSource
+	 */
+	public function testAddSource( $name, $info, $expected ) {
+		$rl = new ResourceLoader;
+		if ( $expected === false ) {
+			$this->setExpectedException( 'MWException', 'ResourceLoader duplicate source addition error' );
+			$rl->addSource( $name, $info );
+		}
+		$rl->addSource( $name, $info );
+		if ( is_array( $expected ) ) {
+			foreach ( $expected as $source ) {
+				$this->assertArrayHasKey( $source, $rl->getSources() );
+			}
+		} else {
+			$this->assertArrayHasKey( $expected, $rl->getSources() );
+		}
+	}
+
 	public static function fakeSources() {
 		return array(
 			'examplewiki' => array(
diff --git a/tests/qunit/suites/resources/mediawiki/mediawiki.test.js b/tests/qunit/suites/resources/mediawiki/mediawiki.test.js
index 96813305da2..0767c9ff37d 100644
--- a/tests/qunit/suites/resources/mediawiki/mediawiki.test.js
+++ b/tests/qunit/suites/resources/mediawiki/mediawiki.test.js
@@ -32,9 +32,7 @@
 
 	mw.loader.addSource(
 		'testloader',
-		{
-			loadScript: QUnit.fixurl( mw.config.get( 'wgScriptPath' ) + '/tests/qunit/data/load.mock.php' )
-		}
+		QUnit.fixurl( mw.config.get( 'wgScriptPath' ) + '/tests/qunit/data/load.mock.php' )
 	);
 
 	QUnit.test( 'Initial check', 8, function ( assert ) {