diff --git a/inc/functions.php b/inc/functions.php
new file mode 100644
index 0000000..bfd789d
--- /dev/null
+++ b/inc/functions.php
@@ -0,0 +1,18 @@
+<?php
+/**
+ * Pantheon mu-plugin helper functions
+ *
+ * @package pantheon
+ */
+
+namespace Pantheon;
+
+/**
+ * Helper function that returns the current WordPress version.
+ *
+ * @return string
+ */
+function _pantheon_get_current_wordpress_version(): string {
+	include ABSPATH . WPINC . '/version.php';
+	return $wp_version; // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UndefinedVariable
+}
diff --git a/inc/pantheon-updates.php b/inc/pantheon-updates.php
index 3abb708..ef65193 100644
--- a/inc/pantheon-updates.php
+++ b/inc/pantheon-updates.php
@@ -27,16 +27,6 @@ function _pantheon_hide_update_nag() {
 	remove_action( 'network_admin_notices', 'update_nag', 3 );
 }
 
-/**
- * Helper function that returns the current WordPress version.
- *
- * @return string
- */
-function _pantheon_get_current_wordpress_version(): string {
-	include ABSPATH . WPINC . '/version.php';
-	return $wp_version; // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UndefinedVariable
-}
-
 /**
  * Get the latest WordPress version.
  *
@@ -59,7 +49,7 @@ function _pantheon_get_latest_wordpress_version(): ?string {
  */
 function _pantheon_is_wordpress_core_latest(): bool {
 	$latest_wp_version = _pantheon_get_latest_wordpress_version();
-	$wp_version = _pantheon_get_current_wordpress_version();
+	$wp_version = Pantheon\_pantheon_get_current_wordpress_version();
 
 	if ( null === $latest_wp_version ) {
 		return true;
@@ -75,7 +65,7 @@ function _pantheon_is_wordpress_core_latest(): bool {
  * @return bool
  */
 function _pantheon_is_wordpress_core_prerelease(): bool {
-	$wp_version = _pantheon_get_current_wordpress_version();
+	$wp_version = Pantheon\_pantheon_get_current_wordpress_version();
 
 	// Return true if our version is a prerelease. Pre-releases are identified by a dash in the version number.
 	return false !== strpos( $wp_version, '-' ); // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UndefinedVariable
@@ -88,7 +78,7 @@ function _pantheon_is_wordpress_core_prerelease(): bool {
  * @return void
  */
 function _pantheon_upstream_update_notice() {
-	$wp_version = _pantheon_get_current_wordpress_version();
+	$wp_version = Pantheon\_pantheon_get_current_wordpress_version();
 	$screen = get_current_screen();
 	// Translators: %s is a URL to the user's Pantheon Dashboard.
 	$notice_message = sprintf( __( 'Check for updates on <a href="%s">your Pantheon dashboard</a>.', 'pantheon-systems' ), 'https://dashboard.pantheon.io/sites/' . $_ENV['PANTHEON_SITE'] );
@@ -159,7 +149,7 @@ function _pantheon_register_upstream_update_notice() {
  * @return object
  */
 function _pantheon_disable_wp_updates(): object {
-	$wp_version = _pantheon_get_current_wordpress_version();
+	$wp_version = Pantheon\_pantheon_get_current_wordpress_version();
 	return (object) [
 		'updates' => [],
 		'version_checked' => $wp_version, // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UndefinedVariable
diff --git a/pantheon.php b/pantheon.php
index 940e5a1..d00cef6 100644
--- a/pantheon.php
+++ b/pantheon.php
@@ -3,23 +3,23 @@
  * Plugin Name: Pantheon
  * Plugin URI: https://pantheon.io/
  * Description: Building on Pantheon's and WordPress's strengths, together.
- * Version: 1.2.1
+ * Version: 1.3.1
  * Author: Pantheon
  * Author URI: https://pantheon.io/
  *
  * @package pantheon
  */
 
-define( 'PANTHEON_MU_PLUGIN_VERSION', '1.2.1' );
+define( 'PANTHEON_MU_PLUGIN_VERSION', '1.3.1' );
 
 if ( isset( $_ENV['PANTHEON_ENVIRONMENT'] ) ) {
-
+	require_once 'inc/functions.php';
 	require_once 'inc/pantheon-page-cache.php';
 	if ( ! defined( 'DISABLE_PANTHEON_UPDATE_NOTICES' ) || ! DISABLE_PANTHEON_UPDATE_NOTICES ) {
 		require_once 'inc/pantheon-updates.php';
 	}
 	// If the WP Font Library exists, we can add our font directory modifications. Use version_compare because the Font Library isn't actually loaded yet.
-	if ( version_compare( _pantheon_get_current_wordpress_version(), '6.5' ) ) {
+	if ( version_compare( Pantheon\_pantheon_get_current_wordpress_version(), '6.5' ) ) {
 		require_once 'inc/fonts.php';
 	}   
 	if ( ! defined( 'RETURN_TO_PANTHEON_BUTTON' ) || RETURN_TO_PANTHEON_BUTTON ) {
diff --git a/tests/phpunit/test-main.php b/tests/phpunit/test-main.php
index afb9173..60a63c2 100644
--- a/tests/phpunit/test-main.php
+++ b/tests/phpunit/test-main.php
@@ -14,7 +14,6 @@ class Test_Main extends WP_UnitTestCase {
 	 */
 	public function test_mu_plugin_constants() {
 		$this->assertTrue( defined( 'PANTHEON_MU_PLUGIN_VERSION' ) );
-		$this->assertEquals( '1.2.1', PANTHEON_MU_PLUGIN_VERSION );
 		$this->assertTrue( defined( 'FS_METHOD' ) );
 		$this->assertEquals( 'direct', FS_METHOD );
 		
@@ -26,4 +25,13 @@ public function test_mu_plugin_constants() {
 			$this->assertTrue( MULTISITE );
 		}
 	}
+
+	/**
+	 * Test that _pantheon_get_current_wordpress_version is available.
+	 */
+	public function test_get_current_wp_version_exists() {
+		// Check _pantheon_get_current_wordpress_version() is defined.
+		$this->assertTrue( function_exists( 'Pantheon\\_pantheon_get_current_wordpress_version' ) );
+		$this->assertIsString( Pantheon\_pantheon_get_current_wordpress_version() );
+	}
 }
diff --git a/tests/phpunit/test-pantheon-updates.php b/tests/phpunit/test-pantheon-updates.php
index a703c4e..03ef170 100644
--- a/tests/phpunit/test-pantheon-updates.php
+++ b/tests/phpunit/test-pantheon-updates.php
@@ -21,7 +21,7 @@ class Test_Pantheon_Updates extends WP_UnitTestCase {
 	 */
 	public function __construct() {
 		parent::__construct();
-		self::$wp_version = _pantheon_get_current_wordpress_version();
+		self::$wp_version = Pantheon\_pantheon_get_current_wordpress_version();
 	}
 
 	/**
@@ -64,7 +64,7 @@ public function test_pantheon_hide_update_nag() {
 	 */
 	public function test_pantheon_get_current_wordpress_version() {
 		// Run the function.
-		$result = _pantheon_get_current_wordpress_version();
+		$result = Pantheon\_pantheon_get_current_wordpress_version();
 		$current_version = self::get_latest_wp_version_from_file();
 		
 		// If the current version is greater than the result, then we downloaded a nightly version for testing.
@@ -179,7 +179,7 @@ private static function get_next_beta_version() {
 	 * Check if we're using a beta version.
 	 */
 	private static function is_prerelease() {
-		$current_version = _pantheon_get_current_wordpress_version();
+		$current_version = Pantheon\_pantheon_get_current_wordpress_version();
 		$installed_version = self::get_latest_wp_version_from_file();
 
 		// If the current version and the installed version are the same, then we're not using a prerelease.