Similar to programs like Mailman or Listserv this extension allows you to run a discussion mailing list.

That means that every email sent to a central email address is forwarded to the rest of the members of the list. When members reply to such emails Mailster again forwards them to the other list recipients.

Mailster allows your users to be part of a group and communicate by email without having to log into your Joomla site.

This is primarily made with discussion email lists (two way communication) in mind, although Mailster can also be used for newsletters.

Features
- For Group communication and newsletters
- Usable with any POP3/IMAP email account
- Recipients are managed by the admin in the backend
- Users can (un)subscribe with frontend plugin or module (optional)
- All Joomla users can be chosen as recipients, additional users can be stored
- Users can be organized in groups
- Single users or whole groups can be added as recipients of a mailing list
- Replies to mailing list posts can be forwarded to all recipients
- Mail archive for browsing the mails
- Full support of HTML emails and attachments
- Seamless installation: all plugins are included and are installed automatically
- English, German, French, Dutch, Italian, Danish, Japanese and Slovenian translation included
- many more features

Designed for all...
- users that are tired of group messaging systems that require another login
- users who want to communicate with their favourite mail client
- admins that are tired of updating personal details on different systems
- admins who want to be able to use users within Joomla as recipients of a mailing list

Changelog
** Version 1.7.10 Bugfix Release (September 9th, 2023)**
- When moderation is active, the list administrators (serving as moderators) should not need to approve their own messages to the list
- Mailster recognizes when the Joomla email sending is disabled (even though the Joomla mailer is used in one or more active mailing lists)
- Profile plugin (editing List subscription in Joomla user profile in backend) works now for Joomla 4
- Fix error: Non-static method PEAR::isError() cannot be called statically
- Fix issue in CB synchronization (when doing actions in CB backend)
- Fix two bugs related to email digests that could prevent digests from being sent
- Case insensitive blocked email addresses check
- Fix some PHP Deprecated messages (PHP 8.1 and later)

** Version 1.7.9 Bugfix Release (August 2nd, 2023)**
- Remove logging to the database since no longer a recommended way to debug
- When formatted HTML with very long lines is encountered, automatic line splitting may run into issues. e.g. when formatted Text from Google Docs is copied into the email body. This is now fixed.
- Fix CB Bride Plugin issue for saving changes in CB "my account" profile
- Avoid errors with empty body/html/attachments under PHP 8.x
- Fix error 1406 Data too long for column references_to
- Fix subscriber module problem with PHP 8.1/8.2
- Avoid PHP Deprecation Warnings under PHP 8.2
- Better capture enqueuing issues

** Version 1.7.8 Bugfix Release (Jan 20th, 2023) **
- Email without TO recipient will not stop email(s) from being retrieved from the mailing list inbox

** Version 1.7.7 Bugfix Release (Jan 1st, 2023) **
- Update Html2Text library
- Changing install script to use utf8mb4 instead of utf8 for the default character set
- Fix for better SMTP debugging
- Fix issue when no iconv functionality is available for charset conversion
- Fix issue to automatically use the core's DB field collation (of content.title) for Mailster's content fields.

** Version 1.7.6 Bugfix Release (November 2nd, 2022) **
- Improve compatibility with PHP 8
- Introduce updateservers to please the Joomla 3.10 update checker ("Pre-Update Check for Joomla 4.x")
- Servers can be deleted again
- Do not render user view when no user record found
- Digest sending mechanism does not produce PHP warning

** Version 1.7.5 Bugfix Release (August 9th, 2022) **
- Improve compatibility with Joomla 4 (custom HTML header/footer shows the configured WYSIWYG editor)
- Fix: storing of attachments with long MIME subtypes is supported and will not crash mail retrieving
- Make sure failure to open the log file will not crash the process
- Fix incompatibility issues with Joomla 4 (JArrayHelper VS ArrayHelper)

Note that this version has limitations (e.g. max. 50 recipients per list) compared to our commercial products Mailster Essential, Business and Ultimate. Find a feature comparison overview here: http://www.brandt-oss.com/index.php/mailster/pricing