ChangemakerStudios/Papercut-SMTP

✨ New Features

• Service Tray Manager - New Windows tray notification application for managing the Papercut SMTP Windows Service. Provides system tray icon with service status, start/stop/restart controls, quick access to the web UI, balloon notifications for new emails, and run-at-startup support. Fixes [#249](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/249)
• Upgrade Dialog with Release Notes - When an update is available, a new dialog shows current vs. new version with rendered release notes so you can review changes before upgrading. Fixes [#344](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/344)
• System Accent Color - Added a "System" option to the theme accent dropdown that reads and syncs with the Windows accent color in real-time. Now the default for new installs. Fixes [#343](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/343)
• Web UI Overhaul - Completely refreshed the Papercut Service web interface:
• Replaced Glyphicons with inline SVGs for a cleaner, dependency-free icon set
• Per-message delete with confirmation via new `DELETE /api/messages/{id}` endpoint
• Auto-refresh toggle button and browser back-button navigation
• Modern visual design with Plus Jakarta Sans font, refined colors, and improved layout
• + 1 more

🐛 Bug Fixes

• FileSystemWatcher Reliability - Fixed emails silently stopping to appear in the UI. Root cause was FileSystemWatcher buffer overflows from excessive NotifyFilter events. Now uses FileName-only filter, 64KB buffer, auto-recreation on faults, and a 30-second periodic fallback refresh. Fixes [#352](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/352)
• Notification Title - Fixed Windows toast notifications showing "velopack.PapercutSMTP" instead of "Papercut SMTP" by using Velopack's native `--aumid` flag at install time. Fixes [#350](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/350)
• CID Embedded Images - Fixed intermittent failure to load Content-ID embedded images in the HTML viewer due to incorrect `file://` URL format and MimeMessage cache state issues
• HTML Email Preview (Web UI) - Fixed iframe collapsing to ~8px and load event race conditions by switching to `$watch`-based rendering with direct document writing, ResizeObserver support, and retry-based height measurement
• Cross-Thread Theme Exception - Fixed crash when Windows system theme changes while the app is running

📦 Improvements

• Security: jQuery & Frontend Library Upgrades - Upgraded jQuery 1.11.0 to 3.7.1 and jQuery UI 1.10.4 to 1.14.1, mitigating CVE-2020-11022 and CVE-2020-11023 (XSS vulnerabilities). Also upgraded AngularJS 1.3.8 to 1.8.3 and Bootstrap 3.3.2 to 3.4.1. Fixes [#353](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/353)
• Aspire Integration Documentation - Added documentation for using Papercut SMTP with .NET Aspire projects, including connection string format and setup examples. (Thanks, [mguinness](https://github.com/mguinness)!)
• Docker Documentation - Added troubleshooting guide for volume permission errors when running with mounted volumes
• Dependencies - Updated NuGet packages and Velopack to v0.0.1521

📦 Contributors

• Special thanks to [AntekOlszewski](https://github.com/AntekOlszewski) for fixing the Delete All race condition and [mguinness](https://github.com/mguinness) for documenting Aspire integration!
• Several features and fixes in this release were developed with the assistance of [Claude Code](https://claude.ai).

📦 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`)
• + 8 more

📦 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!

🐛 Bug Fixes

• Forwarding Rules Failing - Fixed critical bug where email forwarding rules were completely broken due to TaskCanceledException. Fixes [#331](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/331) (Thanks, [wcwhitehead](https://github.com/wcwhitehead)!)
• SSL/TLS Connection Mode - Fixed SSL/TLS connection mode to use SslOnConnect for port 465 and Auto for STARTTLS
• SMTP Timeout - Set proper SMTP timeout of 30 seconds for forwarding rules
• Backend Service Status - Fixed initial status detection for backend service

📦 Contributors

• Special thanks to [wcwhitehead](https://github.com/wcwhitehead) for reporting the critical forwarding rules bug!

✨ New Features

• Search Functionality - Added Ctrl+F search to all message detail views (Message, Body, Headers, and Raw). Fixes [#295](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/295)
• Zoom Controls - Added Ctrl+Mouse Scroll Wheel zoom support to message detail views with persistence and visual indicators. Fixes [#323](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/323)
• Attachment Display - Attachments now display in the main message panel with icons and easy access. Fixes [#112](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/112)
• Context Menu for Links - Right-click context menu added for email links with copy and open functionality. Fixes [#218](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/218)
• Empty State Placeholders - Added smart empty state messaging to message list and detail views for better first-time user experience. Fixes [#268](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/268)
• SMTP Authentication and TLS/STARTTLS Support - Full support for SMTP authentication and TLS/STARTTLS encryption for secure email testing. Fixes [#102](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/102)
• Periodic Background Rules - Added periodic background rule execution with mail retention cleanup to both UI and Service. Related to [#251](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/251)
• Windows Package Manager (winget) Support - Papercut SMTP can now be installed and updated via winget. Fixes [#231](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/231)
• + 3 more

📦 Improvements

• Word-Wrap Support - Added CSS word-wrap support to HTML email rendering for better display of long text strings. Fixes [#154](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/154)
• Non-Standard Email Domains - Added support for non-standard email domains in development environments (e.g., .local, .dev). Fixes [#284](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/284)
• SSL Certificate Error Handling - Added optional SSL certificate error handling for WebView2 to support self-signed certificates. Fixes [#243](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/243)
• Comprehensive Unit Tests - Added extensive unit tests with FluentAssertions for improved code quality and reliability
• NuGet Package Upgrades - Upgraded all NuGet packages to latest versions, including migration to new Polly ResiliencePipeline API
• Service Architecture - Refactored attachment and process handling into dedicated services for better separation of concerns
• Settings Debouncing - Implemented debounced settings saves using Rx Throttle operator to reduce unnecessary I/O

🐛 Bug Fixes

• Window Size Saving - Fixed window size not saving correctly when minimized. Fixes [#327](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/327)
• PDF Attachment Opening - Fixed PDF attachment opening on Windows 11 24H2 and double-click issues. Fixes [#310](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/310), [#280](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/280)
• Message Rendering with # Characters - Fixed message rendering for subjects containing # characters. Fixes [#282](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/282) (Thanks, [xavero](https://github.com/xavero)!)
• SMTP IP Logging - Fixed SMTP service not logging remote client IP address correctly. Fixes [#291](https://github.com/ChangemakerStudios/Papercut-SMTP/issues/291)
• Empty State Flicker - Fixed placeholder flicker when switching between emails
• WebView2 Deserialization - Added robust error handling for WebView2 message deserialization
• Null Safety - Various null safety improvements and fixes throughout the codebase
• Process.Start Null Checks - Added null checks for Process.Start return values to prevent exceptions

📦 Code Quality

• Refactored to use IUiCommandHub.ShowMessage instead of MessageBox.Show for better testability
• Extracted debouncing logic into reusable SettingsSaveDebouncer
• Improved async patterns and error handling in example applications
• Fixed test assertions to use FluentAssertions consistently
• Added nullable reference type attributes throughout codebase

📝 Documentation

• Added comprehensive TLS/STARTTLS setup documentation with Docker examples
• Created example projects: SendEmailTest, SendRichEmailTest, SendWordWrapTest, SendEmailWithTls, SendEmailWithFileLinks
• Improved Docker documentation with troubleshooting guides
• Added installation guide for PowerShell and command-line users

📦 Contributors

• Special thanks to [xavero](https://github.com/xavero) for fixing message rendering with # characters!

📦 Upgrading

• NOTE: Velopack "Auto-Upgrade" doesn't work before this (v7.0.2) version. You must download the setup and re-run it to upgrade. Once you're on this version, the auto-upgrade system will work!

📦 Improvements

• Modernized versioning system to use Directory.Build.props instead of GlobalAssemblyInfo.cs
• Added Windows ARM64 support (#283)
• Improved port configuration for SMTP and HTTP services (#285, #286, #293)
• Enhanced Docker support with non-privileged ports (SMTP: 2525, HTTP: 8080)
• Consolidated documentation and improved Docker build process

🐛 Bug Fixes

• Fixed Windows Service installation and auto-start issues (#294)
• Fixed Linux path separator handling (#292)
• Fixed SMTP server options configuration

📦 Build System

• Refactored build.cake to reduce code duplication
• GitVersion now populates version properties via MSBuild
• Removed deprecated assembly patching approach

📦 Papercut SMTP v7.0.1 [2024-11-08]

• Fixed Run on Startup broken. (Thanks, [rikrak](https://github.com/rikrak)))
• Drop service installation mention from README by @Kissaki in https://github.com/ChangemakerStudios/Papercut-SMTP/pull/278
• Full Changelog: https://github.com/ChangemakerStudios/Papercut-SMTP/compare/7.0.0...7.0.1

📦 Papercut SMTP v7.0.0 [2024-10-18]

• _NOTE: Uninstall any existing Papercut SMTP installations BEFORE installing this new version._
• Upgraded to .NET 8
• Upgraded to latest dependencies (Caliburn Micro, Autofac, MahApps) and associated systems to support .NET 8.
• Switched to [Velopack](https://github.com/velopack/velopack) auto-upgradable installation system. Great project! (Thanks, [caesay](https://github.com/caesay)!)
• Fix for log updating constantly causing unnecessary WebView2 loading. (PR thanks to [arthurzaczek](https://github.com/arthurzaczek))
• Fix for double request when clicking on links in emails. Issue #232.
• Added InvokeProcess Rule (#274)

📦 Papercut SMTP 7.0.0 RC1 [2024-06-8]

• _NOTE: Uninstall any existing Papercut SMTP installations BEFORE installing this new version._
• Upgraded to .NET 8
• Upgraded to latest dependencies (Caliburn Micro, Autofac, MahApps) and associated systems to support .NET 8.
• Switched to [Velopack](https://github.com/velopack/velopack) auto-upgradable installation system. Great project! (Thanks, [caesay](https://github.com/caesay)!)
• Fix for log updating constantly causing unnecessary WebView2 loading. (PR thanks to [arthurzaczek](https://github.com/arthurzaczek))

📋 Changes

• Upgraded to .NET Framework v4.8 (PR thanks to [1Jesper1](https://github.com/1Jesper1))
• Service doesn't overwrite settings on exit anymore.
• Simplified HTTP binding setting for Service. Basically, "http://0.0.0.0" for "all" binding works again.
• Added Attachment Icon (PR thanks to [Cload](https://github.com/Cload))
• Added graceful fall-back support and error message if WebView2 isn't properly installed.
• Fix for checking registry key for installing edge webview2 & version fixes (PR thanks to [1Jesper1](https://github.com/1Jesper1))

📋 Changes

• Moved to Edge (WebView2) for email display providing modern browser support for viewing.
• Support for SVGs.
• Support for newer HTML/CSS display.
• Fixed: Progress bar for Forwarding Dialog displays correctly now.
• Fixed: Multiple issues with the forwarding dialog.
• [#193] Add logging path to settings.json (PR thanks to [1Jesper1](https://github.com/1Jesper1))
• [#192] Adds an option (defaulting to true) to enable popup notifications when a new message is received. (PR thanks to [richardlawley](https://github.com/richardlawley))
• [#189] Use first capital character in text in "proceed" and "cancel" buttons (PR thanks to [1Jesper1](https://github.com/1Jesper1))

📋 Changes

• Moved to .NET Framework 4.7.2
• Upgraded to latest dependencies (Caliburn Micro, Autofac, MahApps)
• Fixed: Window sizes weren't binding properly.
• Converted system to Async.
• Added additional theme colors.
• Updated the logo.
• Fixed: Hide passwords in rules logging output.
• Fixed: Don't show passwords in rules logging output.
• + 3 more

📦 Papercut SMTP v5.7.0 [2020-04-05]

• Renamed product to "Papercut SMTP" to seperate from other products.
• Moved "Readme.eml" and logs to *\ProgramData\Changemaker Studios\Papercut SMTP* allowing it to be deleted.
• Changed default save directory for Papercut UI to *\%ApplicationData%\Changemaker Studios\Papercut SMTP*. Mail in legacy paths are still supported.
• Added support for embedded message mime types and the ability to save the embedded eml.
• Performance improvements loading messages.
• Misc bug fixes.