diff --git a/SampleApplications/NativeApp/src/nativeMain/kotlin/NativeApp.kt b/SampleApplications/NativeApp/src/nativeMain/kotlin/NativeApp.kt
index abe1ae5a..6c0839c6 100644
--- a/SampleApplications/NativeApp/src/nativeMain/kotlin/NativeApp.kt
+++ b/SampleApplications/NativeApp/src/nativeMain/kotlin/NativeApp.kt
@@ -15,10 +15,10 @@ import net.dankito.banking.client.model.parameter.RetrieveTransactions
 import net.dankito.banking.client.model.parameter.TransferMoneyParameter
 import net.dankito.banking.fints.FinTsClient
 import net.dankito.banking.fints.callback.SimpleFinTsClientCallback
+import net.dankito.banking.fints.extensions.toStringWithMinDigits
 import net.dankito.banking.fints.getAccountData
 import net.dankito.banking.fints.model.TanChallenge
 import net.dankito.banking.fints.transferMoney
-import net.dankito.utils.multiplatform.extensions.*
 import util.CsvWriter
 import util.OutputFormat
 
diff --git a/fints4k/build.gradle b/fints4k/build.gradle
index 291a87f6..8398b8b2 100644
--- a/fints4k/build.gradle
+++ b/fints4k/build.gradle
@@ -65,7 +65,7 @@ kotlin {
 
                 implementation("net.codinux.log:kmp-log:1.5.1")
 
-                implementation("org.jetbrains.kotlinx:kotlinx-serialization-core:1.5.1")
+                implementation("org.jetbrains.kotlinx:kotlinx-serialization-core:$kotlinxSerializationVersion")
 
                 implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:$coroutinesVersion")
 
diff --git a/gradle.properties b/gradle.properties
index 125cc6a7..f99ba83b 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -10,6 +10,7 @@ kotlinVersion=1.8.20
 coroutinesVersion=1.7.2
 ktorVersion=2.3.1
 kotlinxDateTimeVersion=0.4.0
+kotlinxSerializationVersion=1.5.1
 
 android.useAndroidX=true
 android.enableJetifier=true
\ No newline at end of file