diff --git a/CHANGELOG.md b/CHANGELOG.md
index 52c7973b7..4885f7e79 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Change Log
 
+## [1.2.3](https://github.com/ably/ably-cocoa/tree/1.2.3)
+
+[Full Changelog](https://github.com/ably/ably-cocoa/compare/1.2.2...1.2.3)
+
+_Fixes issue:_ Publishing messages with `authCallback` is broken after upgrading from 1.1.16 to 1.2.1 [\#1074](https://github.com/ably/ably-cocoa/issues/1074).
+
+_Fixed by pull request:_ Fixes 40012 "Malformed message; invalid clientId" when message has no clientId and credentials can assume any clientId [\#1082](https://github.com/ably/ably-cocoa/pull/1082) ([ricardopereira](https://github.com/ricardopereira))
+
 ## [1.2.2](https://github.com/ably/ably-cocoa/tree/1.2.2)
 
 [Full Changelog](https://github.com/ably/ably-cocoa/compare/1.2.1...1.2.2)
diff --git a/README.md b/README.md
index 40abd59b4..4bfe60713 100644
--- a/README.md
+++ b/README.md
@@ -98,7 +98,7 @@ If you see, for example, a `dyld: Library not loaded: @rpath/SocketRocketAblyFor
 
 ### Manual installation 
 
-1. Get the code from GitHub [from the release page](https://github.com/ably/ably-cocoa/releases/tag/1.2.2), or clone it to get the latest, unstable and possibly underdocumented version: `git clone git@github.com:ably/ably-cocoa.git`
+1. Get the code from GitHub [from the release page](https://github.com/ably/ably-cocoa/releases/tag/1.2.3), or clone it to get the latest, unstable and possibly underdocumented version: `git clone git@github.com:ably/ably-cocoa.git`
 2. Drag the directory `ably-cocoa/ably-cocoa` into your project as a group.
 3. Ably depends on our [SocketRocket Fork](https://github.com/ably-forks/SocketRocket) 0.5.2; get it [from the releases page](https://github.com/ably-forks/SocketRocket/releases/tag/0.5.2-ably-2) and follow [its manual installation instructions](https://github.com/ably-forks/SocketRocket/#installing).
 4. Ably also depends on our [MessagePack Fork](https://github.com/ably-forks/msgpack-objective-C) 0.2.0; get it [from the releases page](https://github.com/ably-forks/msgpack-objective-C/releases/tag/0.2.0-ably-1) and link it into your project.
@@ -124,7 +124,7 @@ If you haven’t yet, you should first check the detailed [documentation](https:
 
 **`ARTPushRegistererDelegate`** is the interface for handling Push activation/deactivation-related actions. The activation process, by default, will check if the `UIApplication.sharedApplication.delegate` has the `ARTPushRegistererDelegate` implementation.
 
-Since version 1.2.2, there's a new way to pass the `ARTPushRegistererDelegate` implementation into the library. It must be used for new apps created with Xcode 12 and later, using the SwiftUI App Lifecycle. You can assign the delegate directly in the client options using the `pushRegistererDelegate` property, without relying on `UIApplicationDelegate`.
+Since version 1.2.3, there's a new way to pass the `ARTPushRegistererDelegate` implementation into the library. It must be used for new apps created with Xcode 12 and later, using the SwiftUI App Lifecycle. You can assign the delegate directly in the client options using the `pushRegistererDelegate` property, without relying on `UIApplicationDelegate`.
 
 Do not forget that `ARTPush` has two corresponding methods that you should call from yours [application(_:didRegisterForRemoteNotificationsWithDeviceToken:)](https://developer.apple.com/documentation/uikit/uiapplicationdelegate/1622958-application) and [application(_:didFailToRegisterForRemoteNotificationsWithError:)](https://developer.apple.com/documentation/uikit/uiapplicationdelegate/1622962-application), passing to them also an `ARTRest` or `ARTRealtime` instance, configured with the authentication setup and other options you need:
 
@@ -726,7 +726,7 @@ For each release, the following needs to be done:
 * Create a new branch `release/x.x.x` (where `x.x.x` is the new version number) from the `main` branch
 * Run `make bump_[major|minor|patch]` to bump the new version number (creates a Git commit)
 * Run [`github_changelog_generator`](https://github.com/github-changelog-generator/github-changelog-generator) to automate the update of the [CHANGELOG](./CHANGELOG.md). This may require some manual intervention, both in terms of how the command is run and how the change log file is modified. Your mileage may vary:
-    * The command you will need to run will look something like this: `github_changelog_generator -u ably -p ably-cocoa --since-tag 1.2.2 --output delta.md`
+    * The command you will need to run will look something like this: `github_changelog_generator -u ably -p ably-cocoa --since-tag 1.2.3 --output delta.md`
     * Using the command above, `--output delta.md` writes changes made after `--since-tag` to a new file
     * The contents of that new file (`delta.md`) then need to be manually inserted at the top of the `CHANGELOG.md`, changing the "Unreleased" heading and linking with the current version numbers
     * Also ensure that the "Full Changelog" link points to the new version tag instead of the `HEAD`
diff --git a/Spec/RealtimeClientConnection.swift b/Spec/RealtimeClientConnection.swift
index cf771a1f9..83e32f721 100644
--- a/Spec/RealtimeClientConnection.swift
+++ b/Spec/RealtimeClientConnection.swift
@@ -250,7 +250,7 @@ class RealtimeClientConnection: QuickSpec {
                             done()
                         case .connected:
                             if let transport = client.internal.transport as? TestProxyTransport, let query = transport.lastUrl?.query {
-                                expect(query).to(haveParam("lib", withValue: "cocoa\(ARTDefault_variant)-1.2.2"))
+                                expect(query).to(haveParam("lib", withValue: "cocoa\(ARTDefault_variant)-1.2.3"))
                             }
                             else {
                                 XCTFail("MockTransport isn't working")
diff --git a/Version.xcconfig b/Version.xcconfig
index e40da039d..aa3bb44be 100644
--- a/Version.xcconfig
+++ b/Version.xcconfig
@@ -1 +1 @@
-CURRENT_PROJECT_VERSION = 1.2.2
+CURRENT_PROJECT_VERSION = 1.2.3