diff --git a/wp-includes/taxonomy.php b/wp-includes/taxonomy.php
index 2f8cef9a8c..71c422d60b 100644
--- a/wp-includes/taxonomy.php
+++ b/wp-includes/taxonomy.php
@@ -345,9 +345,9 @@ function register_taxonomy( $taxonomy, $object_type, $args = array() ) {
 	);
 	$args = wp_parse_args( $args, $defaults );
 
-	if ( strlen( $taxonomy ) > 32 ) {
-		_doing_it_wrong( __FUNCTION__, __( 'Taxonomies cannot exceed 32 characters in length' ), '4.0' );
-		return new WP_Error( 'taxonomy_too_long', __( 'Taxonomies cannot exceed 32 characters in length' ) );
+	if ( empty( $taxonomy ) || strlen( $taxonomy ) > 32 ) {
+		_doing_it_wrong( __FUNCTION__, __( 'Taxonomy names must be between 1 and 32 characters in length.' ), '4.2' );
+		return new WP_Error( 'taxonomy_length_invalid', __( 'Taxonomy names must be between 1 and 32 characters in length.' ) );
 	}
 
 	if ( false !== $args['query_var'] && ! empty( $wp ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 0288f1a7cb..6802788ef2 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-alpha-31448';
+$wp_version = '4.2-alpha-31449';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.