diff --git a/.editorconfig b/.editorconfig
index cb28f789b..be0f4587f 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -32,6 +32,7 @@ ktlint_function_signature_rule_force_multiline_when_parameter_count_greater_or_e
 ktlint_standard_chain-method-continuation = disabled
 ktlint_ignore_back_ticked_identifier = true
 ktlint_standard_multiline-expression-wrapping = disabled
+ktlint_standard_when-entry-bracing = disabled
 
 [{*/build/**/*,**/*keywords*/**,**/*.Generated.kt,**/*$Extensions.kt}]
 ktlint = disabled
diff --git a/build.gradle.kts b/build.gradle.kts
index 54209b4da..bb0df363e 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -153,7 +153,7 @@ allprojects {
     afterEvaluate {
         try {
             configure<KtlintExtension> {
-                version = "1.3.0"
+                version = "1.4.1"
                 // rules are set up through .editorconfig
             }
         } catch (_: UnknownDomainObjectException) {
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/math/mean.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/math/mean.kt
index d4deec31a..40fe9bbce 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/math/mean.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/math/mean.kt
@@ -11,6 +11,7 @@ import kotlin.reflect.full.withNullability
 internal fun <T : Number> Iterable<T>.mean(type: KType, skipNA: Boolean = skipNA_default): Double =
     asSequence().mean(type, skipNA)
 
+@Suppress("UNCHECKED_CAST")
 internal fun <T : Number> Sequence<T>.mean(type: KType, skipNA: Boolean = skipNA_default): Double {
     if (type.isMarkedNullable) {
         return filterNotNull().mean(type.withNullability(false), skipNA)