diff --git a/README.md b/README.md
index c0797fe..ba00a1c 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,10 @@ See the examples for basic usage options
 - increase device object api version to 2 (invalidation of knx flash data stored by older versions)
 - add #pragma once to Arduino plattform to allow derived plattforms
 - change esp32 plattform to use KNX_NETIF
-- fix out-of-boundary write and dereferenced nullpointer access in tunneling support 
+- fix out-of-boundary write and dereferenced nullpointer access in tunneling support
+
+### V2.1.2 - 2024-12-09
+- adds unicast auto ack
 
 ### V2.1.1 - 2024-09-16
 - fix minor bug in TP-Uart Driver (RX queue out of boundary)
diff --git a/library.json b/library.json
index 71fe2eb..b00d5cc 100644
--- a/library.json
+++ b/library.json
@@ -1,6 +1,6 @@
 {
     "name": "knx",
-    "version": "2.1.1",
+    "version": "2.1.2",
     "dependencies": {
     },
     "description": "knx stack",
diff --git a/src/knx/tpuart_data_link_layer.cpp b/src/knx/tpuart_data_link_layer.cpp
index 7828789..de1fa6b 100644
--- a/src/knx/tpuart_data_link_layer.cpp
+++ b/src/knx/tpuart_data_link_layer.cpp
@@ -650,6 +650,15 @@ void TpUartDataLinkLayer::requestConfig()
         _platform.writeUart(U_CONFIGURE_REQ | U_CONFIGURE_MARKER_REQ);
 #endif
 
+    // Set Address for AutoACK Unicast
+    const uint16_t address = _deviceObject.individualAddress();
+    _platform.writeUart(U_SET_ADDRESS_REQ);
+    _platform.writeUart((address >> 8) & 0xFF);
+    _platform.writeUart(address & 0xFF);
+#ifdef NCN5120
+    _platform.writeUart(0xFF); // Dummy Byte needed by NCN only
+#endif
+
     // Abweichende Config
     if (_repetitions != 0b00110011)
     {