v4.5

# BillionMail v4.5 Release Notes  

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## ✨ New Features  

### 📧 Bulk Email Enhancements  
- **Subscription list tag management**  
  Added tag management functionality for subscription groups  
- **Contact activity tracking**  
  Record last active time for each contact  
- **Advanced contact organization**  
  Manage contacts by both tags and groups simultaneously  
- **Batch tag operations**  
  Add/remove multiple tag IDs in bulk for efficient task filtering  
- **Unsubscribe settings**  
  Added unsubscribe configuration options for subscription groups  
- **Improved contact analytics**  
  Enhanced logic for retrieving contact trend data  

### 📨 Email Marketing Upgrades  
- **Tag-based filtering**  
  Marketing tasks now support tag filtering for precise audience targeting  
- **Dynamic task editing**  
  Edit sender addresses, templates, and subjects while tasks are paused - changes apply immediately when resumed  
- **Task duplication**  
  One-click campaign replication for efficient repetitive task creation  

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## ⚙️ Core Optimizations  
- **Unsubscribe template redesign**  
  Completely revamped unsubscribe email templates with improved layout and user experience  
- **Flexible SMTP relay authentication**  
  Added optional authentication support and improved validation logic for non-authenticated relays  
- **Streamlined contact export**  
  Rebuilt export logic with browser-native file download responses  
- **Accurate engagement metrics**  
  Optimized email click-through rate calculation algorithm  

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## 🐛 Bug Fixes  
- **Performance optimization**  
  Fixed high CPU consumption when sending non-variant emails and improved Spintax parsing efficiency  
- **Address validation fix**  
  Resolved false email format errors when updating mail forwarding settings  
- **Stability improvements**  
  Patched various edge cases and minor stability issues across modules