Ticket #23819: 23819.diff

wp-content/themes/twentythirteen/functions.php

@@ -25 +25 @@
  */
 
 /**
+ * Prevent switching to Twenty Thirteen on old versions
+ * of WordPress. Switches to the previously activated theme
+ * or the default theme.
+ */
+function twentythirteen_switch_theme( $theme_name, $theme ) {
+        if ( version_compare( $GLOBALS['wp_version'], '3.6', '>=' ) )
+                return;
+
+        if ( 'twentythirteen' != $theme->template )
+                switch_theme( $theme->template, $theme->stylesheet );
+        elseif ( 'twentythirteen' != WP_DEFAULT_THEME )
+                switch_theme( WP_DEFAULT_THEME );
+
+        unset( $_GET['activated'] );
+        add_action( 'admin_notices', 'twentythirteen_upgrade_notice' );
+}
+add_action( 'after_switch_theme', 'twentythirteen_switch_theme', 10, 2 );
+
+function twentythirteen_upgrade_notice() {
+        $message = sprintf( __( 'Twenty Thirteen requires at least WordPress version 3.6. You are running version %s. Please upgrade and try again.' ), $GLOBALS['wp_version'] );
+        printf( '<div class="error"><p>%s</p></div>', esc_html( $message ) );
+}
+
+/**
  * Sets up the content width value based on the theme's design.
  * @see twentythirteen_content_width() for template-specific adjustments.
  */