diff --git a/tools/visualisePropertyTree/requirements.txt b/tools/visualisePropertyTree/requirements.txt
index e515b15..7014446 100644
--- a/tools/visualisePropertyTree/requirements.txt
+++ b/tools/visualisePropertyTree/requirements.txt
@@ -11,4 +11,4 @@ rdflib==4.2.2
 requests==2.18.1
 six==1.10.0
 SPARQLWrapper==1.8.0
-urllib3==1.21.1
+urllib3==1.26.5