diff --git a/lib/jabber/XMPP/XMLStream.php b/lib/jabber/XMPP/XMLStream.php
index 5c71426200f..41c7a78dea1 100644
--- a/lib/jabber/XMPP/XMLStream.php
+++ b/lib/jabber/XMPP/XMLStream.php
@@ -126,11 +126,11 @@ class XMPPHP_XMLStream {
 	/**
 	 * @var string
 	 */
-	protected $until = '';
+	protected $until = [];
 	/**
 	 * @var string
 	 */
-	protected $until_count = '';
+	protected $until_count = [];
 	/**
 	 * @var array
 	 */
diff --git a/lib/jabber/readme_moodle.txt b/lib/jabber/readme_moodle.txt
index 205c214f61c..38e0bbdaadf 100644
--- a/lib/jabber/readme_moodle.txt
+++ b/lib/jabber/readme_moodle.txt
@@ -2,3 +2,4 @@ Description of XMPPHP (aka jabber) version 0.1rc2-r77 library import into Moodle
 
 MDL-20876 - replaced deprecated split() with explode()
 MDL-52335 - PHP7 variable syntax changes
+MDL-64223 - PHP7.1 compatibility changes