diff --git a/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanChallenge.kt b/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanChallenge.kt
index 01846172..2946830b 100644
--- a/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanChallenge.kt
+++ b/BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanChallenge.kt
@@ -65,7 +65,17 @@ open class TanChallenge(
 
 
     /**
-     * Principally a no-op method, not implemented for all client, only implementing client for not: FinTs4jBankingClient.
+     * Not implemented for all client, only implementing client for now: FinTs4jBankingClient.
+     *
+     * If a TAN expires either when [TanChallenge.tanExpirationTime] or a default timeout (15 min) is exceeded,
+     * you can add a callback to get notified when TAN expired e.g. to close a EnterTanDialog.
+     */
+    open fun addTanExpiredCallback(callback: () -> Unit) {
+
+    }
+
+    /**
+     * Principally a no-op method, not implemented for all client, only implementing client for now: FinTs4jBankingClient.
      *
      * If a TAN is requested for a decoupled TAN method like [TanMethodType.DecoupledTan] or [TanMethodType.DecoupledPushTan],
      * you can add a callback to get notified when user approved TAN in her app e.g. to close a EnterTanDialog.
diff --git a/FinTs4jBankingClient/src/commonMain/kotlin/net/codinux/banking/client/fints4k/FinTs4kMapper.kt b/FinTs4jBankingClient/src/commonMain/kotlin/net/codinux/banking/client/fints4k/FinTs4kMapper.kt
index 51588201..fbbb50f7 100644
--- a/FinTs4jBankingClient/src/commonMain/kotlin/net/codinux/banking/client/fints4k/FinTs4kMapper.kt
+++ b/FinTs4jBankingClient/src/commonMain/kotlin/net/codinux/banking/client/fints4k/FinTs4kMapper.kt
@@ -216,6 +216,10 @@ open class FinTs4kMapper {
         val flickerCode = if (challenge is FlickerCodeTanChallenge) mapFlickerCode(challenge.flickerCode) else null
 
         return object : TanChallenge(type, action, challenge.messageToShowToUser, selectedTanMethodId, tanMethods, selectedTanMediumName, tanMedia, tanImage, flickerCode, user, account, challenge.tanExpirationTime, challenge.challengeCreationTimestamp) {
+            override fun addTanExpiredCallback(callback: () -> Unit) {
+                challenge.addTanExpiredCallback(callback)
+            }
+
             override fun addUserApprovedDecoupledTanCallback(callback: () -> Unit) {
                 challenge.addUserApprovedDecoupledTanCallback(callback)
             }