From ef85b45754f40e76735db230ce2976df3cf6545a Mon Sep 17 00:00:00 2001
From: Lance Willett <nanobar@gmail.com>
Date: Wed, 27 Mar 2013 17:06:19 +0000
Subject: [PATCH] Twenty Thirteen: add back-compat function to avoid activation
 with older WordPress installs. Props kovshenin,  see #23819 and #13780.

git-svn-id: http://core.svn.wordpress.org/trunk@23816 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 .../themes/twentythirteen/functions.php       |  5 ++++
 .../themes/twentythirteen/inc/back-compat.php | 23 +++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 wp-content/themes/twentythirteen/inc/back-compat.php

diff --git a/wp-content/themes/twentythirteen/functions.php b/wp-content/themes/twentythirteen/functions.php
index 6e2e9b042b..a2a467a13b 100644
--- a/wp-content/themes/twentythirteen/functions.php
+++ b/wp-content/themes/twentythirteen/functions.php
@@ -592,3 +592,8 @@ add_action( 'customize_preview_init', 'twentythirteen_customize_preview_js' );
  * Adds support for a custom header image.
  */
 require( get_template_directory() . '/inc/custom-header.php' );
+
+/**
+ * Adds back compat handling for WP versions pre-3.6.
+ */
+require( get_template_directory() . '/inc/back-compat.php' );
diff --git a/wp-content/themes/twentythirteen/inc/back-compat.php b/wp-content/themes/twentythirteen/inc/back-compat.php
new file mode 100644
index 0000000000..f8b899d2e3
--- /dev/null
+++ b/wp-content/themes/twentythirteen/inc/back-compat.php
@@ -0,0 +1,23 @@
+<?php
+/**
+ * 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>', $message );
+}
\ No newline at end of file