diff --git a/public/objects.yaml b/public/objects.yaml
index 18701282..cca85fd7 100644
--- a/public/objects.yaml
+++ b/public/objects.yaml
@@ -100,6 +100,9 @@
   refs:
     attributes: [CvrIds, MvrDvrIds]
 - name: ModelPlot
+- name: MPCAppl
+  level: 1
+  symbolKind: Namespace
 - name: MsgBox
 - name: MultiXvrPlot
   refs:
diff --git a/server/src/language-service/diagnosticsProvider.ts b/server/src/language-service/diagnosticsProvider.ts
index b93a1bb7..0fe6f387 100644
--- a/server/src/language-service/diagnosticsProvider.ts
+++ b/server/src/language-service/diagnosticsProvider.ts
@@ -713,6 +713,10 @@ export function validateObjectReferences(
             diagnostics.push(
                 ...validateCalcPvrIdentifierReferences(obj, refProvider, doc)
             );
+        } else if (obj.isType("UAAppl")) {
+            diagnostics.push(
+                ...validateUAApplReferences(obj, refProvider, doc)
+            );
         } else {
             diagnostics.push(
                 ...validateIdentifierReferences(
@@ -910,6 +914,31 @@ function validateCalcPvrIdentifierReferences(
     ];
 }
 
+function validateUAApplReferences(
+    obj: SepticObject,
+    refProvider: SepticReferenceProvider,
+    doc: ITextDocument
+): Diagnostic[] {
+    for (const object of refProvider.getObjectsByIdentifier(
+        obj.identifier!.name
+    )) {
+        if (object.isType("SmpcAppl", "MPCAppl")) {
+            return [];
+        }
+    }
+    return [
+        createDiagnostic(
+            DiagnosticSeverity.Warning,
+            {
+                start: doc.positionAt(obj.identifier!.start),
+                end: doc.positionAt(obj.identifier!.end),
+            },
+            "Missing reference to SmpcAppl or MPCAppl",
+            DiagnosticCode.missingReference
+        ),
+    ];
+}
+
 const hasReferenceToEvr: RefValidationFunction = (refs: SepticReference[]) => {
     for (const ref of refs) {
         if (ref.obj?.isType("Evr")) {