diff --git a/GSMDriver.st b/GSMDriver.st
index e7ba9a9..3a99ac3 100644
--- a/GSMDriver.st
+++ b/GSMDriver.st
@@ -166,7 +166,8 @@ classes.'>
         <category: 'private'>
         aMsg class messageType = GSM48MMMessage msgAuReq ifTrue: [
             | auth resp |
-            auth := A3A8 COMP128_v3: self auKey rand: aMsg auth data.
+            auth := A3A8 COMP128: phoneConfig auVer ki: self auKey rand: aMsg auth data.	
+
             resp := GSM48AuthResp new.
             resp sres data: (auth copyFrom: 1 to: 4).
 
diff --git a/TestPhone.st b/TestPhone.st
index 4ca4440..876b4bd 100644
--- a/TestPhone.st
+++ b/TestPhone.st
@@ -150,7 +150,7 @@ Object subclass: IPAConfig [
 ]
 
 Object subclass: PhoneConfig [
-    | imsi auKey |
+    | imsi auKey auVer |
 
     <comment: 'I am the config of a phone. I do have an IMSI and such.'>
 
@@ -167,10 +167,22 @@ Object subclass: PhoneConfig [
 
     imsi [ ^ imsi ]
     auKey [ ^ auKey ]
+    auVer [ ^ auVer ]
     auKey: anAuKey [
         auKey := anAuKey.
+	auVer := 3.
     ]
 
+    auKeyV2: anAuKey [
+        auKey := anAuKey.
+        auVer := 2.
+    ]
+
+    auKeyV1: anAuKey [
+        auKey := anAuKey.
+        auVer := 1.
+    ] 
+
     auKeyByteArray [
         ^ auKey isString
             ifTrue:  [