diff --git a/README.md b/README.md
index a7be282..06e89a9 100644
--- a/README.md
+++ b/README.md
@@ -29,13 +29,16 @@ containers permit `extensionElements`.
 Therefore, this extension uses a top-level `bpmn:relationship` as a container, e.g.
 
 ```xml
-  <relationship type="icons">
-    <extensionElements>
-      <icon:iconDefinition id="WebhookIcon" href="data:image/svg+xml,%3Csvg id=&#39;icon&#39; xmlns=&#39;http://www.w3.org/2000/svg&#39; width=&#39;18&#39; height=&#39;18&#39; viewBox=&#39;0 0 32 32&#39;%3E%3Cdefs%3E%3Cstyle%3E .cls-1 %7B fill: none; %7D %3C/style%3E%3C/defs%3E%3Cpath d=&#39;M24,26a3,3,0,1,0-2.8164-4H13v1a5,5,0,1,1-5-5V16a7,7,0,1,0,6.9287,8h6.2549A2.9914,2.9914,0,0,0,24,26Z&#39;/%3E%3Cpath d=&#39;M24,16a7.024,7.024,0,0,0-2.57.4873l-3.1656-5.5395a3.0469,3.0469,0,1,0-1.7326.9985l4.1189,7.2085.8686-.4976a5.0006,5.0006,0,1,1-1.851,6.8418L17.937,26.501A7.0005,7.0005,0,1,0,24,16Z&#39;/%3E%3Cpath d=&#39;M8.532,20.0537a3.03,3.03,0,1,0,1.7326.9985C11.74,18.47,13.86,14.7607,13.89,14.708l.4976-.8682-.8677-.497a5,5,0,1,1,6.812-1.8438l1.7315,1.002a7.0008,7.0008,0,1,0-10.3462,2.0356c-.457.7427-1.1021,1.8716-2.0737,3.5728Z&#39;/%3E%3Crect id=&#39;_Transparent_Rectangle_&#39; data-name=&#39;&#38;lt;Transparent Rectangle&#38;gt;&#39; class=&#39;cls-1&#39; width=&#39;32&#39; height=&#39;32&#39;/%3E%3C/svg%3E" />
-    </extensionElements>
-    <source>Definitions</source>
-    <target>Definitions</target>
-  </relationship>
+<bpmn:definitions id="IconExample" ...>
+  ...
+  <bpmn:relationship type="icons">
+    <bpmn:extensionElements>
+      <icon:iconDefinition id="WebhookIcon" href="data:image/svg+xml,%3Csvg id=&#39;icon&#39; xmlns=&#39;http://www.w3.org/2000/svg&#39; width=&#39;18&#39; height=&#39;18&#39; viewBox=&#39;0 0 32 32&#39;%3E%3Cdefs%3E%3Cstyle%3E .cls-1 %7B fill: none; %7D %3C/style%3E%3C/defs%3E%3Cpath d=&#39;M24,26a3,3,0,1,0-2.8164-4H13v1a5,5,0,1,1-5-5V16a7,7,0,1,0,6.9287,8h6.2549A2.9914,2.9914,0,0,0,24,26Z&#39;/%3E%3Cpath d=&#39;M24,16a7.024,7.024,0,0,0-2.57.4873l-3.1656-5.5395a3.0469,3.0469,0,1,0-1.7326.9985l4.1189,7.2085.8686-.4976a5.0006,5.0006,0,1,1-1.851,6.8418L17.937,26.501A7.0005,7.0005,0,1,0,24,16Z&#39;/%3E%3Cpath d=&#39;M8.532,20.0537a3.03,3.03,0,1,0,1.7326.9985C11.74,18.47,13.86,14.7607,13.89,14.708l.4976-.8682-.8677-.497a5,5,0,1,1,6.812-1.8438l1.7315,1.002a7.0008,7.0008,0,1,0-10.3462,2.0356c-.457.7427-1.1021,1.8716-2.0737,3.5728Z&#39;/%3E%3Crect id=&#39;_Transparent_Rectangle_&#39; data-name=&#39;&#38;lt;Transparent Rectangle&#38;gt;&#39; class=&#39;cls-1&#39; width=&#39;32&#39; height=&#39;32&#39;/%3E%3C/svg%3E"/>
+    </bpmn:extensionElements>
+    <bpmn:source>IconExample</bpmn:source>
+    <bpmn:target>IconExample</bpmn:target>
+  </bpmn:relationship>
+</bpmn:definitions>
 ```
 
 The relationship's `source` and `target` MUST point to the `id` of the `bpmn:definitions` root element.
diff --git a/bpmn-icon.xsd b/bpmn-icon.xsd
index 0f317c6..2325698 100644
--- a/bpmn-icon.xsd
+++ b/bpmn-icon.xsd
@@ -1,6 +1,8 @@
 <xs:schema id="bpmn-icon" version="0.1" 
-    targetNamespace="http://www.omg.org/spec/BPMN/non-normative/Icon"
-    xmlns:icon="http://www.omg.org/spec/BPMN/non-normative/Icon"
+    targetNamespace="https://www.omg.org/spec/BPMN/non-normative/Icon"
+    xmlns:icon="https://www.omg.org/spec/BPMN/non-normative/Icon"
+    xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL"
+    xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI"
     xmlns:xs="http://www.w3.org/2001/XMLSchema"
     elementFormDefault="qualified">
 
diff --git a/example.bpmn b/example.bpmn
index 6b80009..010dc14 100644
--- a/example.bpmn
+++ b/example.bpmn
@@ -1,24 +1,15 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<definitions id="IconExample"
+<bpmn:definitions id="IconExample"
   targetNamespace="http://example.org"
   xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL"
+  xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL"
   xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI"
   xmlns:dc="http://www.omg.org/spec/DD/20100524/DC"
-  xmlns:icon="http://www.omg.org/spec/BPMN/non-normative/Icon"
-  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="
-    http://www.omg.org/spec/BPMN/20100524/MODEL
-    ./BPMN20-with-Icon.xsd
-    http://www.omg.org/spec/BPMN/20100524/DI
-    ./BPMNDI-with-iconRef.xsd
-    http://www.omg.org/spec/DD/20100524/DC
-    ./BPMN/DC.xsd
-    http://www.omg.org/spec/BPMN/non-normative/Icon
-    ./bpmn-icon.xsd
-  ">
-  <process id="ProcessWithIcon">
-    <startEvent id="StartEvent"/>
-  </process>
+  xmlns:icon="https://www.omg.org/spec/BPMN/non-normative/Icon"
+  >
+  <bpmn:process id="ProcessWithIcon">
+    <bpmn:startEvent id="StartEvent"/>
+  </bpmn:process>
   <bpmndi:BPMNDiagram id="BPMNDiagram">
     <bpmndi:BPMNPlane id="BPMNPlane" bpmnElement="ProcessWithIcon">
       <bpmndi:BPMNShape id="StartEvent_di" bpmnElement="StartEvent" icon:iconRef="WebhookIcon">
@@ -26,11 +17,11 @@
       </bpmndi:BPMNShape>
     </bpmndi:BPMNPlane>
   </bpmndi:BPMNDiagram>
-  <relationship type="icons">
-    <extensionElements>
+  <bpmn:relationship type="icons">
+    <bpmn:extensionElements>
       <icon:iconDefinition id="WebhookIcon" href="data:image/svg+xml,%3Csvg id=&#39;icon&#39; xmlns=&#39;http://www.w3.org/2000/svg&#39; width=&#39;18&#39; height=&#39;18&#39; viewBox=&#39;0 0 32 32&#39;%3E%3Cdefs%3E%3Cstyle%3E .cls-1 %7B fill: none; %7D %3C/style%3E%3C/defs%3E%3Cpath d=&#39;M24,26a3,3,0,1,0-2.8164-4H13v1a5,5,0,1,1-5-5V16a7,7,0,1,0,6.9287,8h6.2549A2.9914,2.9914,0,0,0,24,26Z&#39;/%3E%3Cpath d=&#39;M24,16a7.024,7.024,0,0,0-2.57.4873l-3.1656-5.5395a3.0469,3.0469,0,1,0-1.7326.9985l4.1189,7.2085.8686-.4976a5.0006,5.0006,0,1,1-1.851,6.8418L17.937,26.501A7.0005,7.0005,0,1,0,24,16Z&#39;/%3E%3Cpath d=&#39;M8.532,20.0537a3.03,3.03,0,1,0,1.7326.9985C11.74,18.47,13.86,14.7607,13.89,14.708l.4976-.8682-.8677-.497a5,5,0,1,1,6.812-1.8438l1.7315,1.002a7.0008,7.0008,0,1,0-10.3462,2.0356c-.457.7427-1.1021,1.8716-2.0737,3.5728Z&#39;/%3E%3Crect id=&#39;_Transparent_Rectangle_&#39; data-name=&#39;&#38;lt;Transparent Rectangle&#38;gt;&#39; class=&#39;cls-1&#39; width=&#39;32&#39; height=&#39;32&#39;/%3E%3C/svg%3E"/>
-    </extensionElements>
-    <source>IconExample</source>
-    <target>IconExample</target>
-  </relationship>
-</definitions>
+    </bpmn:extensionElements>
+    <bpmn:source>IconExample</bpmn:source>
+    <bpmn:target>IconExample</bpmn:target>
+  </bpmn:relationship>
+</bpmn:definitions>