diff --git a/buildSrc/src/main/kotlin/BuildExtensions.kt b/buildSrc/src/main/kotlin/BuildExtensions.kt
index 04c15b52c..83c9e636d 100644
--- a/buildSrc/src/main/kotlin/BuildExtensions.kt
+++ b/buildSrc/src/main/kotlin/BuildExtensions.kt
@@ -156,8 +156,8 @@ val PluginDependenciesSpec.`gradle-doctor`: PluginDependencySpec
     get() = id(GradleDoctor.pluginId).version(GradleDoctor.version)
 
 val PluginDependenciesSpec.kotest: PluginDependencySpec
-    get() = Kotest.MultiplatformGradlePlugin.let {
-        return id(it.id).version(it.version)
+    get() = Kotest.let {
+        return id(it.gradlePluginId).version(it.version)
     }
 
 val PluginDependenciesSpec.kover: PluginDependencySpec
diff --git a/buildSrc/src/main/kotlin/io/spine/dependency/test/Kotest.kt b/buildSrc/src/main/kotlin/io/spine/dependency/test/Kotest.kt
index 0d71ab2f5..bc5a36c12 100644
--- a/buildSrc/src/main/kotlin/io/spine/dependency/test/Kotest.kt
+++ b/buildSrc/src/main/kotlin/io/spine/dependency/test/Kotest.kt
@@ -35,8 +35,9 @@ package io.spine.dependency.test
  */
 @Suppress("unused", "ConstPropertyName")
 object Kotest {
-    const val version = "6.0.3"
+    const val version = "6.0.4"
     const val group = "io.kotest"
+    const val gradlePluginId = "io.kotest"
     const val assertions = "$group:kotest-assertions-core:$version"
     const val runnerJUnit5 = "$group:kotest-runner-junit5:$version"
     const val runnerJUnit5Jvm = "$group:kotest-runner-junit5-jvm:$version"
@@ -45,6 +46,7 @@ object Kotest {
     const val frameworkEngine = "$group:kotest-framework-engine:$version"
 
     // https://plugins.gradle.org/plugin/io.kotest.multiplatform
+    @Deprecated("The plugin is deprecated. Use `io.kotest` plugin instead.")
     object MultiplatformGradlePlugin {
         const val version = "6.0.0.M4"
         const val id = "io.kotest.multiplatform"
diff --git a/buildSrc/src/main/kotlin/kmp-module.gradle.kts b/buildSrc/src/main/kotlin/kmp-module.gradle.kts
index 7577ed538..4f7ec6398 100644
--- a/buildSrc/src/main/kotlin/kmp-module.gradle.kts
+++ b/buildSrc/src/main/kotlin/kmp-module.gradle.kts
@@ -69,7 +69,6 @@ val about = ""
 plugins {
     kotlin("multiplatform")
     id("detekt-code-analysis")
-    id("io.kotest.multiplatform")
     id("org.jetbrains.kotlinx.kover")
     `project-report`
 }
diff --git a/migrate b/migrate
index 9ccf402da..2fd228d64 100755
--- a/migrate
+++ b/migrate
@@ -49,6 +49,14 @@ cp -a .github-workflows/. ../.github/workflows
 cp -a .github/workflows/. ../.github/workflows
 rm -f ../.github/workflows/detekt-code-analysis.yml # This one is `config`-only workflow.
 
+# 2025-10-28 Remove `ArtifactVersion.kt` and `Text.kt`.
+rm -f ../buildSrc/src/main/kotlin/io/spine/dependency/local/ArtifactVersion.kt
+rm -f ../buildSrc/src/main/kotlin/io/spine/dependency/local/Text.kt
+
+# 2025-10-28 Remove `compile-protobuf.gradle.kts`.
+# It no longer needed because we have `io.spine.protobuf-setup` plugin instead.
+rm -f ../buildSrc/src/main/kotlin/compile-protobuf.gradle.kts
+
 # 2025-10-27 Remove `VersionWriter.kt` and `ProtoTaskExtensions.kt`
 rm -f ../buildSrc/src/main/kotlin/io/spine/gradle/VersionWriter.kt
 rm -f ../buildSrc/src/main/kotlin/io/spine/gradle/protobuf/ProtoTaskExtensions.kt