+/**
+ * Execute changes made in WordPress 4.2.1.
+ *
+ * @since 4.2.1
+ */
+function upgrade_421() {
+}
+
+/**
+ * Execute changes made in WordPress 4.2.2.
+ *
+ * @since 4.2.2
+ */
+function upgrade_422() {
+ global $wp_current_db_version, $wpdb;
+
+ if ( $wp_current_db_version < 31534 ) {
+ $content_length = $wpdb->get_col_length( $wpdb->comments, 'comment_content' );
+
+ if ( is_wp_error( $content_length ) ) {
+ return;
+ }
+
+ if ( false === $content_length ) {
+ $content_length = array(
+ 'type' => 'byte',
+ 'length' => 65535,
+ );
+ } elseif ( ! is_array( $content_length ) ) {
+ $length = (int) $content_length > 0 ? (int) $content_length : 65535;
+ $content_length = array(
+ 'type' => 'byte',
+ 'length' => $length
+ );
+ }
+
+ if ( 'byte' !== $content_length['type'] || 0 === $content_length['length'] ) {
+ // Sites with malformed DB schemas are on their own.
+ return;
+ }
+
+ $allowed_length = intval( $content_length['length'] ) - 10;
+
+ $comments = $wpdb->get_results(
+ "SELECT `comment_ID` FROM `{$wpdb->comments}`
+ WHERE `comment_date_gmt` > '2015-04-26'
+ AND LENGTH( `comment_content` ) >= {$allowed_length}
+ AND ( `comment_content` LIKE '%<%' OR `comment_content` LIKE '%>%' )"
+ );
+
+ foreach ( $comments as $comment ) {
+ wp_delete_comment( $comment->comment_ID, true );
+ }
+ }
+}
+