7.6.2

ChangemakerStudios/Papercut-SMTP7.6.2Nov 11, 2025by github-actions[bot]

AI Summary

Papercut SMTP v7.6.2 brings full dark theme support with automatic Windows dark mode detection and introduces IP allowlist filtering for SMTP and HTTP connections with CIDR notation support. The release also upgrades to .NET 9.0 and includes a complete property editor overhaul for rules configuration.

Key Highlights

Dark Theme Support - Full dark mode with system detection and live theme updates
IP Allowlist Support - CIDR notation filtering for SMTP/HTTP connections
Dynamic Property Editor - Custom MahApps.Metro-compatible editor for rules
Tab Preservation - Selected message detail tab now persists when switching messages
.NET 9.0 Upgrade - Performance improvements and latest framework features

New Features

Dark theme with System/Light/Dark base theme selection and accent color customization
IP allowlist filtering via SmtpServer:AllowedIps setting with CIDR support
Dynamic property editor with reflection-based discovery and intelligent control selection
Theme-aware attachment icons and AvalonEdit syntax highlighting
Fail-closed security for IP validation

Full Release Notes

# Release Notes

## Papercut SMTP v7.6.2 [2025-11-11]

*Release replaces 7.6.1 which had a major issue with email receiving in the UI.*

### New Features

- **Dark Theme Support** - Added full dark theme support with automatic Windows dark mode detection and synchronization. Fixes [#228](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/228) (Thanks, [wonea](https://github.com/wonea)!)
  - System/Light/Dark base theme selection with accent color customization
  - Automatic system dark mode detection with live theme updates
  - AvalonEdit syntax highlighting supports both light and dark modes
  - Theme-aware attachment icons and UI controls throughout the application
- **IP Allowlist Support** - Added IP allowlist filtering for SMTP and HTTP connections with CIDR notation support. Fixes [#333](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/333) (Thanks, [mhkarimi1383](https://github.com/mhkarimi1383)!)
  - Configurable via `SmtpServer:AllowedIps` setting
  - Support for individual IPs (e.g., `192.168.1.100`) and CIDR ranges (e.g., `192.168.1.0/24`)
  - Comprehensive unit tests for IP validation and range matching
  - Fail-closed security - blocks all connections if validation fails
- **Dynamic Property Editor for Rules** - Replaced legacy PropertyGrid with custom MahApps.Metro-compatible dynamic property editor
  - Reflection-based property discovery using System.ComponentModel attributes
  - Intelligent control selection (TextBox, NumericUpDown, ToggleSwitch, PasswordBox)
  - Category-based property organization with smart ordering
  - Resizable GridSplitter between rules list and property editor
  - Full dark theme support in Rules Configuration dialog

### Improvements

- **.NET 9.0 Upgrade** - Upgraded entire solution to .NET 9.0 for improved performance and latest framework features
- **Theme Consistency** - Modernized UI to use dynamic theming with refreshed Options dialog and message list visuals
- **Tab Preservation** - Selected message detail tab (Message/Body/Headers/Raw) now preserved when switching between messages
- **Code Quality** - Fixed numerous compiler warnings and null-safety issues throughout the codebase
- **Resource Management** - Fixed X509Certificate2Collection resource leak
- **Docker Improvements** - Updated container and runtime images for .NET 9.0

### Code Quality

- Comprehensive unit tests for IP allowlist validation
- More flexible SMTP/server startup wiring and options
- Internal robustness improvements with clearer initialization and lifecycle handling
- Better error handling across core components

### Contributors

Special thanks to [wonea](https://github.com/wonea) for requesting dark theme support and [mhkarimi1383](https://github.com/mhkarimi1383) for requesting IP allowlist functionality!