diff --git a/doc/sdbus-c++-class-diagram.png b/doc/sdbus-c++-class-diagram.png
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diff --git a/doc/sdbus-c++-class-diagram.uml b/doc/sdbus-c++-class-diagram.uml
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+++ b/doc/sdbus-c++-class-diagram.uml
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+@startuml
+
+package "Public API" <<frame>> #DDDDDD {
+interface IConnection {
+  +requestName()
+  +enterProcessLoop()
+  +leaveProcessLoop()
+}
+
+interface IObject {
+  +registerMethod()
+  +emitSignal()
+}
+
+interface IObjectProxy {
+  +callMethod()
+  +subscribeToSignal()
+}
+
+class Message {
+  +serialize(...)
+  +deserialize(...)
+  +send()
+  Type msgType
+}
+}
+
+interface IConnectionInternal {
+  +addObjectVTable()
+  +createMethodCall()
+  +createSignal()
+}
+
+class Connection {
+}
+
+class Object {
+  IConnectionInternal& connection
+  string objectPath
+  List interfaces
+  List methods
+}
+
+class ObjectProxy {
+  IConnectionInternal& connection
+  string destination
+  string objectPath
+}
+
+IConnection <|-- Connection
+IConnectionInternal  <|- Connection
+IObject <|-- Object
+IObjectProxy <|-- ObjectProxy
+Connection <-- Object : "use"
+Connection <-- ObjectProxy : "use"
+Message <.. Object : "send/receive"
+Message <.. ObjectProxy : "send/receive"
+
+@enduml