
We’ve just released version 5.7.3 of the Courier iOS SDK — a major update for teams using Courier Inbox to power in-app notifications on iOS.
This release improves performance, reliability, and gives you more flexibility to build the experience you want.
Stronger socket connection handling
Real-time delivery is now more reliable when switching between foreground and background — ideal for mobile apps with dynamic in-app messaging.
New threading model with CourierActor
All Courier.shared functionality now runs on a dedicated thread called CourierActor. This keeps SDK work off the main thread and improves performance across the board.
Fully rebuilt inbox datastore
We’ve rebuilt how messages and events are stored and managed — all now handled exclusively within the CourierActor. This ensures greater reliability and data accuracy.
Simplified listener events
Listening for inbox updates is easier than ever. The new onMessageEvent callback lets you respond to message-level events — giving you the tools to build custom UIs without added complexity.
More tests, more confidence
We added new unit and integration tests to back these updates and support future releases.

Introducing Cross-Device Email Preview: see your email on real devices before you send
Cross-Device Email Preview renders your template on the real clients you pick, from Outlook on Windows to dark mode on iPhone, and returns a screenshot of each one. Pick from 96 clients across 21 apps without leaving Design Studio.

New settings page, easier to use, with new background colors
Courier settings has been redesigned. Workspace pages and developer pages are grouped separately, every page says what it's for, and the app now comes in light or dark with nine background colors.

Broadcasts: send one-time messages to your users, right from Courier
Broadcasts lets you send a one-time message to a group of your users, now or on a schedule, without leaving Courier.