diff --git a/build.gradle b/build.gradle
index d5a313b07a..551708d4e4 100644
--- a/build.gradle
+++ b/build.gradle
@@ -2,7 +2,7 @@
 
 buildscript {
     ext {
-        kotlin_version = '1.8.10'
+        kotlin_version = '1.8.21'
         core_version = '1.10.0'
         rxjava_version = '3.1.6'
         rxandroid_version = '3.0.2'
diff --git a/core/ns-sdk/src/main/java/info/nightscout/sdk/NSAndroidClientImpl.kt b/core/ns-sdk/src/main/java/info/nightscout/sdk/NSAndroidClientImpl.kt
index 7f8c934aa2..1f07e76a17 100644
--- a/core/ns-sdk/src/main/java/info/nightscout/sdk/NSAndroidClientImpl.kt
+++ b/core/ns-sdk/src/main/java/info/nightscout/sdk/NSAndroidClientImpl.kt
@@ -292,14 +292,11 @@ class NSAndroidClientImpl(
                     lastModified = response.body()?.lastModified
                 )
             } else throw UnknownResponseNightscoutException()
-        } else if (response.code() in 400..499) {
-            return@callWrapper CreateUpdateResponse(
-                response = response.code(),
-                identifier = null,
-                errorResponse = response.errorBody()?.string() ?: response.message()
-            )
-        } else
-            throw UnsuccessfullNightscoutException(response.errorBody()?.string() ?: response.message())
+        } else return@callWrapper CreateUpdateResponse(
+            response = response.code(),
+            identifier = null,
+            errorResponse = response.errorBody()?.string() ?: response.message()
+        )
     }
 
     override suspend fun createTreatment(nsTreatment: NSTreatment): CreateUpdateResponse = callWrapper(dispatcher) {
diff --git a/gradle.properties b/gradle.properties
index 873792f7a9..3b47fa6324 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -24,3 +24,11 @@ android.useAndroidX=true
 android.nonTransitiveRClass=true
 # Cache is causeing issues with CircleCI nad maybe Studio 2021
 # org.gradle.unsafe.configuration-cache=true
+
+# After migration to kotlin 1.8.21
+#e: org.jetbrains.kotlin.backend.common.BackendException: Backend Internal error: Exception during psi2ir
+# File being compiled: (37,18) in /home/circleci/project/core/interfaces/src/main/java/info/nightscout/interfaces/pump/defs/PumpCapability.kt
+# The root cause org.jetbrains.kotlin.psi2ir.generators.ErrorExpressionException was thrown at: org.jetbrains.kotlin.psi2ir.generators.ErrorExpressionGenerator.generateErrorCall(ErrorExpressionGenerator.kt:100)
+# null: KtCallExpression
+# https://youtrack.jetbrains.com/issue/KT-58027
+kapt.use.jvm.ir=false