Release v21.0

Email Queue System

Centralized queue for all outbound marketing emails with unified delivery for broadcasts and automations.

New Features

• Priority-based email queue with retry logic and per-integration rate limiting
• Background worker with graceful shutdown support
• Automation timeline events: automation.start and automation.end tracking
• Single-tick execution: Process multiple automation nodes per scheduler tick (up to 10 nodes)

Schema Changes

• New email_queue table with 5 optimized indexes
• Added enqueued_count column to broadcasts table
• Added automation_id column to automation_node_executions for analytics
• New index idx_message_history_broadcast_id for broadcast queries

Breaking Changes

• Broadcast statuses renamed: sending → processing, sent → processed