Update changelog versions in messaging.
# Unreleased
+
+# 23.1.1
* [fixed] Fixed deadlock when handling simultaneous messages.
+
+## Kotlin
+The Kotlin extensions library transitively includes the updated
+`firebase-messaging` library. The Kotlin extensions library has no additional
+updates.
+
# 23.1.0
* [unchanged] Updated to accommodate the release of the updated
[messaging_longer] Kotlin extensions library.
