diff --git a/eiffel-vocabulary/EiffelActivityTriggeredEvent.md b/eiffel-vocabulary/EiffelActivityTriggeredEvent.md
index f5f8af15..c181d603 100644
--- a/eiffel-vocabulary/EiffelActivityTriggeredEvent.md
+++ b/eiffel-vocabulary/EiffelActivityTriggeredEvent.md
@@ -9,10 +9,10 @@ __Type:__ String
 __Required:__ Yes  
 __Description:__ The name of the activity. Uniqueness is not required or checked, but is useful.
 
-### data.category
-__Type:__ String  
+### data.categories
+__Type:__ String[]  
 __Required:__ No  
-__Description:__ The category of the activity. This can be used to group multiple similar activities for analysis and visualization purposes. Example usage is to label the similar but unique build activities of all the components of system X as "System X Component Build" (whereas the name would be e.g. "System X Component Y Build").
+__Description:__ Any categorization of the activity. This can be used to group multiple similar activities for analysis and visualization purposes. Example usage is to label the similar but unique build activities of all the components of system X as "System X Component Build" (whereas the name would be e.g. "System X Component Y Build").
 
 ### data.triggers
 __Type:__ Object[]  
diff --git a/examples/events/EiffelActivityTriggeredEvent/simple-customdata.json b/examples/events/EiffelActivityTriggeredEvent/simple-customdata.json
index 4d9d22f6..2b4f43e1 100644
--- a/examples/events/EiffelActivityTriggeredEvent/simple-customdata.json
+++ b/examples/events/EiffelActivityTriggeredEvent/simple-customdata.json
@@ -10,7 +10,9 @@
   },
   "data": {
     "name": "Component X Build",
-    "category": "Component Build",
+    "categories": [
+      "Component Build"
+    ],
     "triggers": [
       {
         "type": "MANUAL",
diff --git a/examples/events/EiffelActivityTriggeredEvent/simple.json b/examples/events/EiffelActivityTriggeredEvent/simple.json
index d95cf507..527b703d 100644
--- a/examples/events/EiffelActivityTriggeredEvent/simple.json
+++ b/examples/events/EiffelActivityTriggeredEvent/simple.json
@@ -10,7 +10,9 @@
   },
   "data": {
     "name": "Component X Build",
-    "category": "Component Build",
+    "categories": [
+      "Component Build"
+    ],
     "triggers": [
       {
         "type": "MANUAL",
diff --git a/schemas/EiffelActivityTriggeredEvent.json b/schemas/EiffelActivityTriggeredEvent.json
index 42efdb83..dec49590 100644
--- a/schemas/EiffelActivityTriggeredEvent.json
+++ b/schemas/EiffelActivityTriggeredEvent.json
@@ -72,8 +72,11 @@
         "name": {
           "type": "string"
         },
-        "category": {
-          "type": "string"
+        "categories": {
+          "type": "array",
+          "items": {
+            "type": "string"
+          }
         },
         "triggers": {
           "type": "array",