# Core v5.3.1
**Release Date:** January 17, 2025  
**Tags:** BUG FIXES, TRADING, WEBSOCKET

## Fixed
- Orderbook subscription payload matching for Kucoin provider causing WebSocket connection failures
- Frontend subscription system not receiving orderbook data when using Kucoin exchange provider
- WebSocket subscription key mismatches between frontend and backend for provider-specific limits
- Unsubscription handling missing from market data WebSocket handler causing memory leaks
- Provider-specific orderbook limit adjustments breaking subscription matching system 