diff --git a/README.md b/README.md
index 7e2b592..bcd6774 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,8 @@ URL query parameters
 --------------------
 
 - `useskinversion`: Like `useskin` but for overriding the Vector skin version
-  user preference and configuration.
+  user preference and configuration. E.g.,
+  http://localhost:8181?useskin=vector&useskinversion=2.
 
 Skin preferences
 ----------------
diff --git a/includes/Constants.php b/includes/Constants.php
index e1b0c22..a39359c 100644
--- a/includes/Constants.php
+++ b/includes/Constants.php
@@ -72,6 +72,13 @@ final class Constants {
 	 */
 	public const REQUIREMENT_FULLY_INITIALISED = 'FullyInitialised';
 
+	// These are used for query parameters.
+	/**
+	 * Override the skin version user preference and site Config. See readme.
+	 * @var string
+	 */
+	public const QUERY_PARAM_SKIN_VERSION = 'useskinversion';
+
 	/**
 	 * This class is for namespacing constants only. Forbid construction.
 	 * @throws FatalError
diff --git a/includes/SkinVector.php b/includes/SkinVector.php
index 29a0010..f061826 100644
--- a/includes/SkinVector.php
+++ b/includes/SkinVector.php
@@ -21,7 +21,7 @@
  * @file
  * @ingroup Skins
  */
-use Vector\Constants;
+use Vector\SkinVersionLookup;
 
 /**
  * Skin subclass for Vector
@@ -36,6 +36,21 @@ class SkinVector extends SkinTemplate {
 
 	private $responsiveMode = false;
 
+	/**
+	 * @var SkinVersionLookup
+	 */
+	private $skinVersionLookup;
+
+	/**
+	 * @inheritDoc
+	 */
+	public function __construct( $skinname = null ) {
+		parent::__construct( $skinname );
+
+		$this->skinVersionLookup =
+			new SkinVersionLookup( $this->getRequest(), $this->getUser(), $this->getConfig() );
+	}
+
 	/**
 	 * Enables the responsive mode
 	 */
@@ -67,7 +82,8 @@ class SkinVector extends SkinTemplate {
 	public function getDefaultModules() {
 		$modules = parent::getDefaultModules();
 		// add vector skin styles and vector module
-		$module = $this->isLegacy() ? 'skins.vector.styles.legacy' : 'skins.vector.styles';
+		$module = $this->skinVersionLookup->isLegacy()
+			? 'skins.vector.styles.legacy' : 'skins.vector.styles';
 		$modules['styles']['skin'][] = $module;
 		$modules['core'][] = 'skins.vector.js';
 
@@ -85,9 +101,7 @@ class SkinVector extends SkinTemplate {
 	 */
 	protected function setupTemplate( $classname ) {
 		$tp = new TemplateParser( __DIR__ . '/templates' );
-		$vectorTemplate = new VectorTemplate( $this->getConfig(), $tp, $this->isLegacy() );
-
-		return $vectorTemplate;
+		return new VectorTemplate( $this->getConfig(), $tp, $this->skinVersionLookup->isLegacy() );
 	}
 
 	/**
@@ -98,15 +112,4 @@ class SkinVector extends SkinTemplate {
 	public function shouldPreloadLogo() {
 		return true;
 	}
-
-	/**
-	 * Whether or not the legacy skin is being used.
-	 *
-	 * @return bool
-	 */
-	private function isLegacy() {
-		// Note: This will be replaced with FeatureManager when it is ready.
-		return $this->getUser()->getOption( Constants::PREF_KEY_SKIN_VERSION )
-			=== Constants::SKIN_VERSION_LEGACY;
-	}
 }
diff --git a/includes/SkinVersionLookup.php b/includes/SkinVersionLookup.php
new file mode 100644
index 0000000..8b43a3f
--- /dev/null
+++ b/includes/SkinVersionLookup.php
@@ -0,0 +1,109 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @since 1.35
+ */
+
+namespace Vector;
+
+use Config;
+use User;
+use WebRequest;
+
+/**
+ * Given initial dependencies, retrieve the current skin version. This class does no parsing, just
+ * the lookup.
+ *
+ * Skin version is evaluated in the following order:
+ *
+ * - useskinversion URL query parameter override. See readme.
+ *
+ * - User preference. The User object for new and existing accounts are updated by hook according to
+ *   VectorDefaultSkinVersionForNewAccounts and VectorDefaultSkinVersionForExistingAccounts. See
+ *   Hooks and skin.json.
+ *
+ *   If the skin version is evaluated prior to User preference hook invocations, an incorrect
+ *   version may be returned as only query parameter and site configuration will be known.
+ *
+ * - Site configuration default. The default is controlled by VectorDefaultSkinVersion. This is used
+ *   for anonymous users and as a fallback configuration. See skin.json.
+ *
+ * @unstable
+ *
+ * @package Vector
+ * @internal
+ */
+final class SkinVersionLookup {
+	/**
+	 * @var WebRequest
+	 */
+	private $request;
+	/**
+	 * @var User
+	 */
+	private $user;
+	/**
+	 * @var Config
+	 */
+	private $config;
+
+	/**
+	 * This constructor accepts all dependencies needed to obtain the skin version. The dependencies
+	 * are lazily evaluated, not cached, meaning they always return the current results.
+	 *
+	 * @param WebRequest $request
+	 * @param User $user
+	 * @param Config $config
+	 */
+	public function __construct( WebRequest $request, User $user, Config $config ) {
+		$this->request = $request;
+		$this->user = $user;
+		$this->config = $config;
+	}
+
+	/**
+	 * Whether or not the legacy skin is being used.
+	 *
+	 * @return bool
+	 * @throws \ConfigException
+	 */
+	public function isLegacy() {
+		return $this->getVersion() === Constants::SKIN_VERSION_LEGACY;
+	}
+
+	/**
+	 * The skin version as a string. E.g., `Constants::SKIN_VERSION_LEGACY`,
+	 * `Constants::SKIN_VERSION_LATEST`, or maybe 'beta'. Note: it's likely someone will put arbitrary
+	 * strings in the query parameter which means this function returns those strings as is.
+	 *
+	 * @return string
+	 * @throws \ConfigException
+	 */
+	public function getVersion() {
+		// Obtain the skin version from the `useskinversion` URL query parameter override, the user
+		// preference, or the configured default.
+		return (string)$this->request->getVal(
+			Constants::QUERY_PARAM_SKIN_VERSION,
+			$this->user->getOption(
+				Constants::PREF_KEY_SKIN_VERSION,
+				$this->config->get( Constants::CONFIG_KEY_DEFAULT_SKIN_VERSION )
+			)
+		);
+	}
+}
diff --git a/skin.json b/skin.json
index c058412..f4620b9 100644
--- a/skin.json
+++ b/skin.json
@@ -24,6 +24,7 @@
 	"AutoloadClasses": {
 		"Vector\\Constants": "includes/Constants.php",
 		"Vector\\Hooks": "includes/Hooks.php",
+		"Vector\\SkinVersionLookup": "includes/SkinVersionLookup.php",
 		"SkinVector": "includes/SkinVector.php",
 		"VectorTemplate": "includes/VectorTemplate.php"
 	},
diff --git a/tests/phpunit/integration/SkinVersionLookupTest.php b/tests/phpunit/integration/SkinVersionLookupTest.php
new file mode 100644
index 0000000..59fa77a
--- /dev/null
+++ b/tests/phpunit/integration/SkinVersionLookupTest.php
@@ -0,0 +1,133 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @since 1.35
+ */
+
+use Vector\SkinVersionLookup;
+
+/**
+ * @group Vector
+ * @coversDefaultClass \Vector\SkinVersionLookup
+ */
+class SkinVersionLookupTest extends \MediaWikiTestCase {
+	/**
+	 * @covers ::isLegacy
+	 * @covers ::getVersion
+	 */
+	public function testRequest() {
+		$request = $this->getMockBuilder( \WebRequest::class )->getMock();
+		$request
+			->expects( $this->exactly( 2 ) )
+			->method( 'getVal' )
+			->with( $this->anything(), $this->equalTo( '1' ) )
+			->willReturn( 'beta' );
+
+		$user = $this->createMock( \User::class );
+		$user
+			->expects( $this->exactly( 2 ) )
+			->method( 'getOption' )
+			->with( $this->anything(), $this->equalTo( '2' ) )
+			->willReturn( '1' );
+
+		$config = new HashConfig( [ 'VectorDefaultSkinVersion' => '2' ] );
+
+		$skinVersionLookup = new SkinVersionLookup( $request, $user, $config );
+
+		$this->assertSame(
+			$skinVersionLookup->getVersion(),
+			'beta',
+			'Query parameter is the first priority.'
+		);
+		$this->assertSame(
+			$skinVersionLookup->isLegacy(),
+			false,
+			'Version is non-legacy.'
+		);
+	}
+
+	/**
+	 * @covers ::getVersion
+	 * @covers ::isLegacy
+	 */
+	public function testUserPreference() {
+		$request = $this->getMockBuilder( \WebRequest::class )->getMock();
+		$request
+			->expects( $this->exactly( 2 ) )
+			->method( 'getVal' )
+			->with( $this->anything(), $this->equalTo( '1' ) )
+			->willReturn( '1' );
+
+		$user = $this->createMock( \User::class );
+		$user
+			->expects( $this->exactly( 2 ) )
+			->method( 'getOption' )
+			->with( $this->anything(), $this->equalTo( '2' ) )
+			->willReturn( '1' );
+
+		$config = new HashConfig( [ 'VectorDefaultSkinVersion' => '2' ] );
+
+		$skinVersionLookup = new SkinVersionLookup( $request, $user, $config );
+
+		$this->assertSame(
+			$skinVersionLookup->getVersion(),
+			'1',
+			'User preference is the second priority.'
+		);
+		$this->assertSame(
+			$skinVersionLookup->isLegacy(),
+			true,
+			'Version is legacy.'
+		);
+	}
+
+	/**
+	 * @covers ::getVersion
+	 * @covers ::isLegacy
+	 */
+	public function testConfig() {
+		$request = $this->getMockBuilder( \WebRequest::class )->getMock();
+		$request
+			->expects( $this->exactly( 2 ) )
+			->method( 'getVal' )
+			->with( $this->anything(), $this->equalTo( '2' ) )
+			->willReturn( '2' );
+
+		$user = $this->createMock( \User::class );
+		$user
+			->expects( $this->exactly( 2 ) )
+			->method( 'getOption' )
+			->with( $this->anything(), $this->equalTo( '2' ) )
+			->willReturn( '2' );
+
+		$config = new HashConfig( [ 'VectorDefaultSkinVersion' => '2' ] );
+
+		$skinVersionLookup = new SkinVersionLookup( $request, $user, $config );
+
+		$this->assertSame(
+			$skinVersionLookup->getVersion(),
+			'2',
+			'Config is the third priority.'
+		);
+		$this->assertSame(
+			$skinVersionLookup->isLegacy(),
+			false,
+			'Version is non-legacy.'
+		);
+	}
+}