UXC v0.12.1 has been released, supporting message subscription and IM. UXC is a unified protocol invocation layer, initially addressing the unified invocation of interfaces like OpenAPI, GraphQL, and MCP. With this version, I wanted to add another capability: subscription. When developing an event-driven agent, I quickly encountered a problem: many scenarios don't end with a single API call; events continuously arrive, requiring the agent to decide how to handle them. In this case, request/response alone isn't enough; a unified subscription runtime is also needed. But the problem isn't just "whether events can be received." Directly dumping all events onto the agent would be costly, and in many scenarios, it couldn't handle the load. The context would be overwhelmed by the event stream, and scheduling would become awkward. A more suitable approach is to first store subscribed events in a local file or other addressable state, then process them periodically according to a strategy. This way, the agent sees pre-filtered and filtered input, rather than a flood of raw events. IM is the most obvious example of this scenario. Because instant messaging (IM) is inherently a continuous stream of events: receiving messages, sending messages, receiving events, and then integrating them into a longer automated process. Therefore, this version first adds the IM component. Currently integrated IMs include Telegram, Slack, Matrix, Discord, and Feishu/Lark, and also cover scenarios like LINE, WhatsApp, and DingTalk. Besides IM, this subscription runtime can now systematically handle event sources such as GraphQL subscriptions (Bitquery), WebSocket (Binance/OKX price events), and JSON-RPC subscribe (Ethereum/Suite). Feedback is welcome. Repo: