diff --git a/.github/workflows/build-on-ubuntu.yml b/.github/workflows/build-on-ubuntu.yml
index 01f6fd71a..b07bf0fb0 100644
--- a/.github/workflows/build-on-ubuntu.yml
+++ b/.github/workflows/build-on-ubuntu.yml
@@ -87,7 +87,7 @@ jobs:
       # there anyway).
       - name: Upload code coverage report
         if: steps.codecov.outputs.available == 'true' || github.event_name == 'push'
-        uses: codecov/codecov-action@v4
+        uses: codecov/codecov-action@v7
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           fail_ci_if_error: true
diff --git a/.idea/kotlinc.xml b/.idea/kotlinc.xml
index 85d8f5503..5c4b3ef9d 100644
--- a/.idea/kotlinc.xml
+++ b/.idea/kotlinc.xml
@@ -7,4 +7,4 @@
     <option name="externalSystemId" value="Gradle" />
     <option name="version" value="2.3.21" />
   </component>
-</project>
+</project>
\ No newline at end of file
diff --git a/buildSrc/src/main/kotlin/io/spine/dependency/local/Compiler.kt b/buildSrc/src/main/kotlin/io/spine/dependency/local/Compiler.kt
index ff79b3c69..e3b4d0aa4 100644
--- a/buildSrc/src/main/kotlin/io/spine/dependency/local/Compiler.kt
+++ b/buildSrc/src/main/kotlin/io/spine/dependency/local/Compiler.kt
@@ -27,6 +27,8 @@
 package io.spine.dependency.local
 
 import io.spine.dependency.Dependency
+import io.spine.dependency.local.Compiler.DF_VERSION_ENV
+import io.spine.dependency.local.Compiler.VERSION_ENV
 
 /**
  * Dependencies on the Spine Compiler modules.
@@ -72,7 +74,7 @@ object Compiler : Dependency() {
      * The version of the Compiler dependencies.
      */
     override val version: String
-    private const val fallbackVersion = "2.0.0-SNAPSHOT.056"
+    private const val fallbackVersion = "2.0.0-SNAPSHOT.057"
 
     /**
      * The distinct version of the Compiler used by other build tools.
@@ -81,7 +83,7 @@ object Compiler : Dependency() {
      * transitive dependencies, this is the version used to build the project itself.
      */
     val dogfoodingVersion: String
-    private const val fallbackDfVersion = "2.0.0-SNAPSHOT.056"
+    private const val fallbackDfVersion = "2.0.0-SNAPSHOT.057"
 
     /**
      * The artifact for the Compiler Gradle plugin.
diff --git a/buildSrc/src/main/kotlin/io/spine/dependency/local/Logging.kt b/buildSrc/src/main/kotlin/io/spine/dependency/local/Logging.kt
index 04d19ea52..e9f477ac3 100644
--- a/buildSrc/src/main/kotlin/io/spine/dependency/local/Logging.kt
+++ b/buildSrc/src/main/kotlin/io/spine/dependency/local/Logging.kt
@@ -33,7 +33,7 @@ package io.spine.dependency.local
  */
 @Suppress("ConstPropertyName", "unused")
 object Logging {
-    const val version = "2.0.0-SNAPSHOT.417"
+    const val version = "2.0.0-SNAPSHOT.419"
     const val group = Spine.group
 
     const val loggingArtifact = "spine-logging"
diff --git a/buildSrc/src/main/kotlin/io/spine/gradle/kotlin/KotlinConfig.kt b/buildSrc/src/main/kotlin/io/spine/gradle/kotlin/KotlinConfig.kt
index 92b7a3874..0e5099a77 100644
--- a/buildSrc/src/main/kotlin/io/spine/gradle/kotlin/KotlinConfig.kt
+++ b/buildSrc/src/main/kotlin/io/spine/gradle/kotlin/KotlinConfig.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2025, TeamDev. All rights reserved.
+ * Copyright 2026, TeamDev. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -55,20 +55,26 @@ fun KotlinJvmProjectExtension.applyJvmToolchain(version: String) =
  */
 @Suppress("unused")
 fun KotlinCommonCompilerOptions.setFreeCompilerArgs() {
+    val optIns = mutableListOf(
+        "kotlin.contracts.ExperimentalContracts",
+        "kotlin.ExperimentalUnsignedTypes",
+        "kotlin.ExperimentalStdlibApi",
+        "kotlin.experimental.ExperimentalTypeInference",
+    )
     if (this is KotlinJvmCompilerOptions) {
         jvmDefault.set(JvmDefaultMode.NO_COMPATIBILITY)
+        // `kotlin.io.path` ships only in the JVM standard library, so for common
+        // and Native compilations this opt-in marker is unresolved and the compiler
+        // warns about it. Scope it to JVM compilations; multiplatform common and
+        // Native code cannot use the API anyway.
+        optIns.add("kotlin.io.path.ExperimentalPathApi")
     }
     freeCompilerArgs.addAll(
         listOf(
             "-Xskip-prerelease-check",
             "-Xexpect-actual-classes",
             "-Xcontext-parameters",
-            "-opt-in=" +
-                    "kotlin.contracts.ExperimentalContracts," +
-                    "kotlin.io.path.ExperimentalPathApi," +
-                    "kotlin.ExperimentalUnsignedTypes," +
-                    "kotlin.ExperimentalStdlibApi," +
-                    "kotlin.experimental.ExperimentalTypeInference",
+            "-opt-in=" + optIns.joinToString(separator = ","),
         )
     )
 }
diff --git a/config b/config
index 03e67ea0e..3f13608b3 160000
--- a/config
+++ b/config
@@ -1 +1 @@
-Subproject commit 03e67ea0e2652a73d6f24fe22caad8a0bf130cc1
+Subproject commit 3f13608b3bb1a8bc736fbb748b95ec3dc11843a2
diff --git a/contexts/context-tests/src/testFixtures/kotlin/io/spine/logging/context/AbstractContextDataProviderSpec.kt b/contexts/context-tests/src/testFixtures/kotlin/io/spine/logging/context/AbstractContextDataProviderSpec.kt
index ab96ad2c0..a36b8493d 100644
--- a/contexts/context-tests/src/testFixtures/kotlin/io/spine/logging/context/AbstractContextDataProviderSpec.kt
+++ b/contexts/context-tests/src/testFixtures/kotlin/io/spine/logging/context/AbstractContextDataProviderSpec.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2025, TeamDev. All rights reserved.
+ * Copyright 2026, TeamDev. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -87,6 +87,15 @@ abstract class AbstractContextDataProviderSpec {
     private companion object {
         private val FOO = MetadataKey.single<String>("foo")
         private val BAR = MetadataKey.repeated<String>("bar")
+
+        /**
+         * A custom [MetadataKey] created by subclassing rather than via the factory
+         * functions, reproducing the scenario from
+         * [issue #70](https://github.com/SpineEventEngine/logging/issues/70).
+         */
+        private val CUSTOM =
+            object : MetadataKey<String>("custom", String::class, canRepeat = false) {}
+
         private val SUB_TASK = ScopeType.create("sub task")
         private val BATCH_JOB = ScopeType.create("batch job")
     }
@@ -157,6 +166,30 @@ abstract class AbstractContextDataProviderSpec {
             checkCallbackWasExecuted()
         }
 
+        /**
+         * Verifies that a custom [MetadataKey] — created by subclassing rather than via
+         * the factory functions — can be attached to a context and is delivered to the
+         * context metadata.
+         *
+         * This is a regression test for
+         * [issue #70](https://github.com/SpineEventEngine/logging/issues/70), where
+         * passing a custom key to `withMetadata` used to throw a `ClassCastException`
+         * on the JVM.
+         */
+        @Test
+        fun `with a custom metadata key`() {
+            val value = "custom-value"
+            contextMetadata.shouldBeEmpty()
+            context.newContext()
+                .withMetadata(CUSTOM, value)
+                .call {
+                    contextMetadata.shouldUniquelyContain(CUSTOM, value)
+                    markCallbackExecuted()
+                }
+            contextMetadata.shouldBeEmpty()
+            checkCallbackWasExecuted()
+        }
+
         @Test
         fun `with a log level map`() {
             val defaultLevel = TLevel.FINE
diff --git a/docs/dependencies/dependencies.md b/docs/dependencies/dependencies.md
index 756a07893..10a70642b 100644
--- a/docs/dependencies/dependencies.md
+++ b/docs/dependencies/dependencies.md
@@ -1,6 +1,6 @@
 
 
-# Dependencies of `io.spine:spine-logging-context-tests:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-context-tests:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : org.jetbrains. **Name** : annotations. **Version** : 26.1.0.
@@ -441,14 +441,14 @@
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-fixtures:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-fixtures:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 ## Compile, tests, and tooling
@@ -1240,14 +1240,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:45 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-grpc-context:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-grpc-context:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -2094,14 +2094,14 @@ This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-jul-backend:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-jul-backend:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -2932,14 +2932,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:46 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-jvm-default-platform:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-jvm-default-platform:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -3786,14 +3786,14 @@ This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:46 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-jvm-jul-backend-grpc-context:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-jvm-jul-backend-grpc-context:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -4692,14 +4692,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-jvm-jul-backend-std-context:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-jvm-jul-backend-std-context:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -5590,14 +5590,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-jvm-log4j2-backend-std-context:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-jvm-log4j2-backend-std-context:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -6508,14 +6508,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-jvm-slf4j-jdk14-backend-std-context:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-jvm-slf4j-jdk14-backend-std-context:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -7414,14 +7414,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-jvm-slf4j-reload4j-backend-std-context:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-jvm-slf4j-reload4j-backend-std-context:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -8324,14 +8324,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-log4j2-backend:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-log4j2-backend:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -9206,14 +9206,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 ## Compile, tests, and tooling
@@ -10013,14 +10013,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:45 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine.tools:logging-testlib:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine.tools:logging-testlib:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 ## Compile, tests, and tooling
@@ -10832,14 +10832,14 @@ This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:44 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-otel-backend:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-otel-backend:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 ## Compile, tests, and tooling
@@ -11739,14 +11739,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:45 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-otel-backend-bootstrap:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-otel-backend-bootstrap:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.auto.service. **Name** : auto-service-annotations. **Version** : 1.1.1.
@@ -13157,14 +13157,14 @@ This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-probe-backend:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-probe-backend:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.auto.service. **Name** : auto-service-annotations. **Version** : 1.1.1.
@@ -14015,14 +14015,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:43 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-smoke-test:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-smoke-test:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.fasterxml.jackson. **Name** : jackson-bom. **Version** : 2.22.0.
@@ -14921,14 +14921,14 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:44 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
 
 
 
 
-# Dependencies of `io.spine:spine-logging-std-context:2.0.0-SNAPSHOT.419`
+# Dependencies of `io.spine:spine-logging-std-context:2.0.0-SNAPSHOT.420`
 
 ## Runtime
 1.  **Group** : com.google.code.findbugs. **Name** : jsr305. **Version** : 3.0.2.
@@ -15759,6 +15759,6 @@ This report was generated on **Sun Jun 28 21:04:41 WEST 2026** using
 
 The dependencies distributed under several licenses, are used according their commercial-use-friendly license.
 
-This report was generated on **Sun Jun 28 21:04:42 WEST 2026** using 
+This report was generated on **Tue Jun 30 00:13:44 WEST 2026** using 
 [Gradle-License-Report plugin](https://github.com/jk1/Gradle-License-Report) by Evgeny Naumenko, licensed under 
 [Apache 2.0 License](https://github.com/jk1/Gradle-License-Report/blob/master/LICENSE).
\ No newline at end of file
diff --git a/docs/dependencies/pom.xml b/docs/dependencies/pom.xml
index cc46af21e..963ad82a1 100644
--- a/docs/dependencies/pom.xml
+++ b/docs/dependencies/pom.xml
@@ -10,7 +10,7 @@ all modules and does not describe the project structure per-subproject.
  -->
 <groupId>io.spine</groupId>
 <artifactId>logging</artifactId>
-<version>2.0.0-SNAPSHOT.419</version>
+<version>2.0.0-SNAPSHOT.420</version>
 
 <inceptionYear>2015</inceptionYear>
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index df6a6ad76..a9db11550 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.6.1-bin.zip
 networkTimeout=10000
 retries=0
 retryBackOffMs=500
diff --git a/gradlew b/gradlew
index b9bb139f7..249efbb03 100755
--- a/gradlew
+++ b/gradlew
@@ -20,7 +20,7 @@
 
 ##############################################################################
 #
-#   Gradle start up script for POSIX generated by Gradle.
+#   gradlew start up script for POSIX generated by Gradle.
 #
 #   Important for running:
 #
@@ -29,7 +29,7 @@
 #       bash, then to run this script, type that shell name before the whole
 #       command line, like:
 #
-#           ksh Gradle
+#           ksh gradlew
 #
 #       Busybox and similar reduced shells will NOT work, because this script
 #       requires all of these POSIX shell features:
diff --git a/gradlew.bat b/gradlew.bat
index 24c62d56f..a51ec4f58 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -19,7 +19,7 @@
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
 @rem
-@rem  Gradle startup script for Windows
+@rem  gradlew startup script for Windows
 @rem
 @rem ##########################################################################
 
@@ -72,7 +72,7 @@ echo location of your Java installation. 1>&2
 
 
 
-@rem Execute Gradle
+@rem Execute gradlew
 @rem endlocal doesn't take effect until after the line is parsed and variables are expanded
 @rem which allows us to clear the local environment before executing the java command
 endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
diff --git a/logging/src/commonMain/kotlin/io/spine/logging/MetadataKey.kt b/logging/src/commonMain/kotlin/io/spine/logging/MetadataKey.kt
index 51c898e6c..5c6347fe8 100644
--- a/logging/src/commonMain/kotlin/io/spine/logging/MetadataKey.kt
+++ b/logging/src/commonMain/kotlin/io/spine/logging/MetadataKey.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2025, TeamDev. All rights reserved.
+ * Copyright 2026, TeamDev. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -64,6 +64,14 @@ import kotlin.reflect.KClass
  * to be loaded very early in the logging platform lifecycle without risking any static
  * initialization issues.
  *
+ * A key can be created either through a factory function — [single] or [repeated] on this
+ * class, or `singleMetadataKey` / `repeatedMetadataKey` on
+ * [LoggingFactory] — or by subclassing this class to
+ * customize value formatting (see the protected constructor and the [emit] methods below).
+ * Both kinds of keys are accepted wherever a `MetadataKey` is expected, including the
+ * `withMetadata` method of the
+ * [ScopedLoggingContext.Builder][io.spine.logging.context.ScopedLoggingContext.Builder].
+ *
  * Custom subclasses of `MetadataKey` which override either of the protected [.emit] methods
  * should take care to avoid calling any code, which might trigger logging since this could lead
  * to unexpected recursion, especially if the key is being logged as part of a
diff --git a/logging/src/jvmMain/kotlin/io/spine/logging/LoggingFactory.kt b/logging/src/jvmMain/kotlin/io/spine/logging/LoggingFactory.kt
index 9ee77f2fa..1b701d8ce 100644
--- a/logging/src/jvmMain/kotlin/io/spine/logging/LoggingFactory.kt
+++ b/logging/src/jvmMain/kotlin/io/spine/logging/LoggingFactory.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright 2025, TeamDev. All rights reserved.
+ * Copyright 2026, TeamDev. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -61,8 +61,8 @@ public actual object LoggingFactory {
     ): MetadataKey<T> = MetadataKey.single(label, valueClass)
 
     @JvmStatic
-    public fun <T: Any> singleMetadataKey(label: String, type: Class<T>): MetadataKey<T> =
-        singleMetadataKey(label, type.kotlin)
+    public fun <T : Any> singleMetadataKey(label: String, valueClass: Class<T>): MetadataKey<T> =
+        singleMetadataKey(label, valueClass.kotlin)
 
     @JvmStatic
     public actual fun <T : Any> repeatedMetadataKey(
@@ -71,8 +71,8 @@ public actual object LoggingFactory {
     ): MetadataKey<T> = MetadataKey.repeated(label, valueClass)
 
     @JvmStatic
-    public fun <T : Any> repeatedMetadataKey(label: String, type: Class<T>): MetadataKey<T> =
-        repeatedMetadataKey(label, type.kotlin)
+    public fun <T : Any> repeatedMetadataKey(label: String, valueClass: Class<T>): MetadataKey<T> =
+        repeatedMetadataKey(label, valueClass.kotlin)
 
     private fun createForClass(cls: Class<*>): Logger {
         val loggerBackend = Platform.getBackend(cls.name)
diff --git a/version.gradle.kts b/version.gradle.kts
index d3b1ef081..6e7a6c334 100644
--- a/version.gradle.kts
+++ b/version.gradle.kts
@@ -24,4 +24,4 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-val versionToPublish: String by extra("2.0.0-SNAPSHOT.419")
+val versionToPublish: String by extra("2.0.0-SNAPSHOT.420")