diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/CustomerAccount.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/CustomerAccount.kt
index 7759298b..91634410 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/CustomerAccount.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/CustomerAccount.kt
@@ -32,6 +32,9 @@ open class CustomerAccount(
 ) : CustomerCredentials(bankCode, loginName, password) {
 
 
+    internal constructor() : this("", "", "", "", "", "") // for object deserializers
+
+
     override fun toString(): String {
         return "$bankName $loginName"
     }
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/FinTsClientResponse.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/FinTsClientResponse.kt
index a781ab3c..9156967a 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/FinTsClientResponse.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/FinTsClientResponse.kt
@@ -12,6 +12,9 @@ open class FinTsClientResponse(
   open val finTsModel: BankData? = null
 ) {
 
+  internal constructor() : this(null, null, listOf()) // for object deserializers
+
+
   open val successful: Boolean
     get() = error == null
 
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/GetAccountDataResponse.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/GetAccountDataResponse.kt
index dfe9284d..6811a3c1 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/GetAccountDataResponse.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/client/model/response/GetAccountDataResponse.kt
@@ -13,6 +13,9 @@ open class GetAccountDataResponse(
     finTsModel: BankData? = null
 ) : FinTsClientResponse(error, errorMessage, messageLogWithoutSensitiveData, finTsModel) {
 
+    internal constructor() : this(null, null, null, listOf()) // for object deserializers
+
+
     open val retrievedTransactions: List<AccountTransaction>
         get() = customerAccount?.accounts?.flatMap { it.bookedTransactions } ?: listOf()
 
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/messages/datenelemente/implementierte/tan/TanMedium.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/messages/datenelemente/implementierte/tan/TanMedium.kt
index 59d41f60..9b714949 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/messages/datenelemente/implementierte/tan/TanMedium.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/messages/datenelemente/implementierte/tan/TanMedium.kt
@@ -18,7 +18,7 @@ open class TanMedium(
 ) {
 
 
-    internal constructor() : this(TanMediumKlasse.AlleMedien, TanMediumStatus.Verfuegbar, null)
+    internal constructor() : this(TanMediumKlasse.AlleMedien, TanMediumStatus.Verfuegbar, null) // for object deserializers
 
 
     override fun equals(other: Any?): Boolean {