The text provides a comprehensive guide for migrating from Pusher to PubNub, emphasizing a two-phase approach to ensure a seamless transition and enhancement of chat application features. It details the necessary steps for both solo developers and teams, offering a concise tutorial for setting up PubNub's Managed Connectivity Platform (MCP) and utilizing an AI-assisted workflow to expedite the process. Phase 1 focuses on a conservative migration, replacing Pusher with PubNub while preserving existing architecture by matching API signatures and ensuring rollback capabilities. Phase 2, mandatory for chat apps using the Chat SDK, introduces enhancements such as typing indicators, which are non-optional, while documenting additional features like read receipts and message threads for optional implementation. The guide also explains the conceptual differences between Pusher and PubNub, including channel and event handling, authentication methods, and the use of PubNub's Access Manager for managing permissions. Additionally, it provides a decision tree to help determine whether to use PubNub's Chat SDK or Core SDK based on the application's use case, offering a cheat sheet for transitioning from Pusher to PubNub.