# Courier Mail Server

> mail-server software suite

**Wikidata**: [Q1137680](https://www.wikidata.org/wiki/Q1137680)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Courier_Mail_Server)  
**Source**: https://4ort.xyz/entity/courier-mail-server

## Summary
Courier Mail Server is a free and open-source mail-server software suite licensed under the GNU General Public License (GPL). It provides email services for Unix-like operating systems, including Linux and IBM AIX, and has been actively maintained since its inception in May 2000. The software supports protocols like IMAP and includes components such as SQWebMail and Maildrop for comprehensive email management.

## Key Facts
- **Inception**: May 2000.
- **License**: GNU General Public License (free software).
- **Supported Platforms**: Linux, IBM AIX, BSD, and Solaris.
- **Latest Version**: 1.5.1 (released October 23, 2025).
- **Programming Language**: Primarily written in C.
- **Key Components**: Courier-IMAP, SQWebMail, Maildrop.
- **File Format**: Uses the Maildir format for email storage.

## FAQs
### Q: Is Courier Mail Server free to use?
A: Yes, it is free software distributed under the GNU General Public License, allowing users to run, modify, and distribute the software.

### Q: What operating systems does Courier Mail Server support?
A: It runs on Linux, IBM AIX, BSD (including FreeBSD and OpenBSD), and Solaris.

### Q: Is Courier Mail Server still actively maintained?
A: Yes, as of 2025, the latest version (1.5.1) was released in October 2025, indicating ongoing development.

## Why It Matters
Courier Mail Server plays a significant role in email infrastructure as a reliable, open-source solution for Unix-like systems. Its modular design (e.g., separate IMAP, SMTP, and webmail components) allows flexibility for administrators to customize email services. Supporting multiple platforms, including legacy systems like IBM AIX, ensures compatibility in diverse environments. As a GPL-licensed tool, it promotes transparency and community-driven improvement, contributing to its longevity since 2000. It remains relevant for organizations prioritizing open-source software and interoperability with modern email standards.

## Notable For
- **GPL Licensing**: Ensures freedom to modify and distribute, aligning with open-source principles.
- **Cross-Platform Support**: Compatible with Linux, BSD, Solaris, and IBM AIX, including older enterprise systems.
- **Modular Architecture**: Includes standalone tools like Courier-IMAP and Maildrop for spam filtering.
- **Active Maintenance**: Regular updates (e.g., 1.5.1 in 2025) despite its age, addressing security and functionality.

## Body
### History and Development
- **Initial Release**: May 2000.
- **Repository**: Hosted on GitHub and SourceForge, with code available at [https://github.com/svarshavchik/courier.git](https://github.com/svarshavchik/courier.git).
- **Programming Language**: Primarily developed in C.

### Technical Specifications
- **Protocols Supported**: SMTP, IMAP, POP3, and webmail access via SQWebMail.
- **Storage Format**: Uses Maildir for efficient email storage.
- **Components**:
  - **Courier-IMAP**: Implements the IMAP protocol.
  - **Maildrop**: A filter for spam and email processing.
  - **SQWebMail**: A webmail interface.

### Versions
- **0.75.0**: Released June 28, 2015.
- **1.0.9**: Stable version released August 29, 2019.
- **1.5.1**: Latest stable version (October 23, 2025), available on SourceForge.

### Platform Support
- **Operating Systems**: Verified to run on Linux, IBM AIX, BSD variants, and Solaris.
- **Package Availability**: Included in Debian, Ubuntu, Gentoo, and OpenSUSE repositories.

### Licensing and Distribution
- **License**: GNU General Public License (GPL).
- **Copyright Status**: Copyrighted software distributed under GPL terms.

### Community and Documentation
- **Website**: [https://www.courier-mta.org/](https://www.courier-mta.org/) (English).
- **Documentation**: Guides available on the official website and Arch Wiki.

## References

1. [The courier Open Source Project on Open Hub: Languages Page. Open Hub](https://www.openhub.net/p/courier/analyses/latest/languages_summary)
2. [Source](https://www.courier-mta.org/)
3. [Source](http://www.courier-mta.org/download.html)
4. [Source](https://sourceforge.net/projects/courier/files/courier/1.0.9/)
5. [Browse /courier/1.3.4](https://sourceforge.net/projects/courier/files/courier/1.3.4/)
6. [Source](https://sourceforge.net/projects/courier/files/courier/1.5.1/)
7. Freebase Data Dumps. 2013
8. [Source](https://www.courier-mta.org/repo.html)