April 2026 - Mailman-users - lists.mailman3.org

Guidance Request: Migrating Existing Mailman 3 Installation to Docker-Based Deployment
by Prasanth Nair April 20, 2026

April 20, 2026

Hi all, I am currently running a Mailman 3 setup on a standalone server and planning to migrate it to a Docker-based deployment using the official Docker Mailman images. I would appreciate your guidance on the recommended approach for this migration. *Current (existing) setup:* - Mailman Core: 3.3.5 - Postorius: 1.3.6 - HyperKitty: 1.3.5 - PostgreSQL: 12.22 (Ubuntu) - Host-based installation (non-Docker) - Postfix used as the MTA - Active mailing lists with members and archives - Apache reverse proxy in front *Target (new) setup:* - Docker-based Mailman 3 (mailman-core, mailman-web, PostgreSQL containers) - Based on the official Docker Mailman repository - Postfix as the MTA - Apache reverse proxy in front I would like to migrate the following components safely: - Mailing lists and their configurations - Subscribers and roles - HyperKitty archives - Postorius/web data (users, preferences, etc.) I have a few specific questions: 1. What is the recommended migration approach from a host-based Mailman 3 installation to the Docker-based setup? 2. Is it safe to directly restore the PostgreSQL databases into the Docker environment, or is there a preferred migration method? 3. Are there any version compatibility considerations when migrating from Mailman Core 3.3.5 / Postorius 1.3.6 / HyperKitty 1.3.5 to the versions used in the current Docker images? 4. How to migrate archives? 5. The official Docker Compose file references `postgres:12-alpine`. Is it recommended to stay on PostgreSQL 12 for compatibility, or is it supported to use a newer PostgreSQL version (for example, PostgreSQL 18) with the Docker Mailman setup? 6. Are there any common pitfalls or best practices you would recommend for ensuring a smooth migration? Any guidance or documentation you can provide would be greatly appreciated. Thank you for your time and support. Kind regards, Prasanth Nair

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request to held messages yields set of email addresses
by Thomas Krichel April 16, 2026

April 16, 2026

Hi gang, I probably have already developed an uneviable reputation of being able to produce the finest of mess. I stay true to form here. In my 3.12 installation when my admin clicks to view the held messages, he gets an internal server error. The error comes from postorius, where the log entry is 2026-04-15 12:45:25 [FALCON] [ERROR] GET /3.1/lists/bibnez(a)folks.email/held => Traceback (most recent call last): File "falcon/app.py", line 440, in falcon.app.App.__call__ File "/usr/local/mailman/venv/lib/python3.12/site-packages/mailman/rest/post_moderation.py", line 194, in on_get resource = self._make_collection(request) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/local/mailman/venv/lib/python3.12/site-packages/mailman/rest/helpers.py", line 189, in _make_collection [etag(resource) for resource in entries] ^^^^^^^^^^^^^^ File "/usr/local/mailman/venv/lib/python3.12/site-packages/mailman/rest/helpers.py", line 104, in etag return json.dumps(resource, cls=ExtendedEncoder, ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3.12/json/__init__.py", line 238, in dumps **kw).encode(obj) ^^^^^^^^^^^ File "/usr/lib/python3.12/json/encoder.py", line 200, in encode chunks = self.iterencode(o, _one_shot=True) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3.12/json/encoder.py", line 258, in iterencode return _iterencode(o, 0) ^^^^^^^^^^^^^^^^^ File "/usr/local/mailman/venv/lib/python3.12/site-packages/mailman/rest/helpers.py", line 68, in default return super().default(obj) ^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3.12/json/encoder.py", line 180, in default raise TypeError(f'Object of type {o.__class__.__name__} ' TypeError: Object of type set is not JSON serializable Checking the actual set that is returned, by converting the set into a string and writing it to a file (by enhancing helpers.py), I discover that what is returned is as set of 53 email addresses, not of 24 messages as the web interface suggests. Intrestingly, my admin reports that the he is correctly informed about the held messages via email. The then forwards those that need posting to the list. I suspect that to get to the bottom of this problem, I need to use the low-level postorious functions that actually access the parse the held message data. -- Written by Thomas Krichel http://openlib.org/home/krichel on his 22230th day.

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How can we solve ZoneInfoNotFoundError
by Markus Grandpré April 14, 2026

April 14, 2026

Dear list members A user of our Mailman system reports having trouble logging in to access a mailing list archive. In the error messages that the Mailman system sends via email, we find: ... Internal Server Error: /mailman3/accounts/login/ ZoneInfoNotFoundError at /accounts/login/ 'No time zone found with key US/Eastern' Request Method: POST Request URL: https://mailman.uni-konstanz.de/mailman3/accounts/login/ Django Version: 4.2.28 Python Executable: /usr/bin/uwsgi-core Python Version: 3.13.5 ... Exception Type: ZoneInfoNotFoundError at /accounts/login/ Exception Value: 'No time zone found with key US/Eastern' Raised during: allauth.account.views.LoginView Request information: USER: **** GET: No GET data POST: csrfmiddlewaretoken = 'E6IT1iObdZYMyGKUgAHSxJ6LCzSZPDOKZmgVCaN9Kaae3s5gJy75Dwh8ptWjzcdI' login = '****' password = '****' next = '/mailman3/hyperkitty/list/basex-talk(a)mailman.uni-konstanz.de/' FILES: No FILES data COOKIES: csrftoken = '********************' ... (full error stack is attached to this email) Is there a server-side solution available for our GNU Mailman system 3.3.10 (Tom Sawyer), which runs on Debian GNU/Linux 13 (trixie)? Best regards, Markus Grandpré -- Markus Grandpré (he/him) Universität Konstanz Kommunikations-, Informations- und Medienzentrum (KIM) Abteilung IT-Dienste Forschung, Lehre und Infrastruktur Sachgebiet Diensteadministration 78457 Konstanz Tel: +49 7531 88-4342D

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Changing default language for lists
by Wessel Kraaij April 13, 2026

April 13, 2026

How can I change the default language for lists (and other defaults)? I changed it in mailman-core but Postorius overrides these core defaults with a patch. I am using the docker version of maxking Wessel

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Why is it so difficult to setup Mailman3?
by htfoot＠gmail.com April 11, 2026

April 11, 2026

I've been using Mailman2 for probably 20 years, and recently I've been looking to move up to Mailman3 on an Ubuntu system. I think I've got the mailing list core part working, but the instructions for setting up the web part(s) are either inscrutable or incomplete, if not both. Is this just a rite of passage?

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broken route to accounts
by Thomas Krichel April 10, 2026

April 10, 2026

I am using apache to run the web interface, and my Postel port, and I have the proxy routs ProxyPass "/mailman3" "http://127.0.0.1:4386/mailman3" works ProxyPass "/archives" "http://127.0.0.1:4386/archives" works ProxyPass "/accounts" "http://127.0.0.1:4386/accounts" is broken ProxyPass "/admin" "http://127.0.0.1:4386/admin" works ProxyPass "/user-profile" "http://127.0.0.1:4386/user-profile" works What does "is broken" mean here? Well, since I have debug on, GET "http://127.0.0.1:4386/accounts" yields something like (shortened to cut to the salient matter) | <body> | <p> | Using the URLconf defined in <code>mailman_web.urls</code>, | Django tried these URL patterns, in this order: | </p> | <ol> | <li>postorius/</li> | <li>hyperkitty/</li> | <li>mailman3/</li> | <li>archives/</li> | <li>^user-profile/delete$ | [name='mm_user_account_delete']</li> | <li>^user-profile/$ | [name='mm_user_profile']</li> | <li>accounts/</li> | <li>admin/</li> | </ol> | <p> | The current path, <code>accounts</code>, didn’t match any of these. | </p> | </body> Sure I have accounts/ rather than accounts, but neither are working routes endowed with a trailing slash. Digging for mailman_web.urls, I am lead to believe this is related to my settings, and as I inspect them, I am reminded that I appended del ACCOUNT_AUTHENTICATION_METHOD ACCOUNT_LOGIN_METHODS = {'email', 'username'} del ACCOUNT_EMAIL_REQUIRED ACCOUNT_SIGNUP_FIELDS = ['email*', 'username*', 'password1*', 'password2*'] to my settings file. Commenting these lines out, restarting mailmanweb, still the same error. Ideally an error like this should be shown to the user. Instead it leads to a endlessly repeated requests for users to verify their email address, as seen in my live system at say https://lists.repec.info/accounts/confirm-email/ These have no CSS, pointing to an apache missconfiguration For what it's worth, here is my current apache configuration | <VirtualHost *:443> | ServerName lists.repec.info | ServerAlias www.lists.repec.info | ServerAlias list.repec.info | ServerAlias www.list.repec.info | ServerAdmin webmaster@localhost | | RewriteEngine On | RewriteRule "^/?$" "https://lists.repec.info/mailman3/lists/" [R] | | Alias /static "/usr/local/mailman/web/static" | <Directory "/usr/local/mailman/web/static"> | Require all granted | </Directory> | | Alias /favicon.ico "/usr/local/mailman/web/static/postorius/img/favicon.ico" | | <IfModule mod_headers.c> | RequestHeader unset X-Forwarded-Proto | <If "%{HTTPS} =~ /on/"> | RequestHeader set X-Forwarded-Proto "https" | </If> | </IfModule> | | <IfModule mod_proxy.c> | ProxyPreserveHost On | ProxyPassMatch ^/static/ ! | ProxyPass "/mailman3" "http://127.0.0.1:4386/mailman3" | ProxyPass "/archives" "http://127.0.0.1:4386/archives" | ProxyPass "/accounts" "http://127.0.0.1:4386/accounts" | ProxyPass "/admin" "http://127.0.0.1:4386/admin" | ProxyPass "/user-profile" "http://127.0.0.1:4386/user-profile" | </IfModule> | | LogLevel debug | ErrorLog /var/log/apache2/lists.repec.info_error.log | | CustomLog /var/log/apache2/lists.repec.info_access.log combined | ServerSignature On | | Include /etc/letsencrypt/options-ssl-apache.conf | SSLCertificateFile /etc/letsencrypt/opt/live/repec.info/fullchain.pem | SSLCertificateKeyFile /etc/letsencrypt/opt/live/repec.info/privkey.pem | | </VirtualHost> -- Written by Thomas Krichel http://openlib.org/home/krichel on his 22209th day.

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Integration with spamassassin?
by Peter Chubb April 9, 2026

April 9, 2026

Has anyone integrated Mailman3 with Spamassassin? What I'd like is a way for emails that I click 'discard' on in Postorius, to be submitted to the spamassassin Bayes classifier to make it more likely similar ones will be rejected in future at SMTP conversation time. Peter C

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Re: Python 3.13 compatibility
by Thomas Krichel April 2, 2026

April 2, 2026

Hi gang, On mailman import21, I hit the error TypeError: 'pathlib._local.PosixPath' object does not support the context manager protocol I found the earlier thread, where Mark wrote > This is https://gitlab.com/mailman/mailman/-/issues/1190 fixed for > Mailman 3.3.11 by https://gitlab.com/mailman/mailman/-/merge_requests/1309 I have (venv) mailman@darni:~$ mailman version GNU Mailman 3.3.9 (Tom Sawyer) I tried (venv) mailman@darni:~$ pip install -U mailman postorius django-mailman3 hyperkitty mailman-web to no avail, the TypeError is not fixed and the version is the same. ok, so I need to spell out a version. Trying pip install -U mailman==3.3.11 postorius django-mailman3 hyperkitty mailman-web 3.3.11 appears not to be available pip install -U mailman==3.3.10 postorius django-mailman3 hyperkitty mailman-web yields the familiar problem with the nntplib. ERROR: Could not find a version that satisfies the requirement nntplib; python_version >= "3.13" (from mailman) (from versions: none) ERROR: No matching distribution found for nntplib; python_version >= "3.13" I had earlier gotten around this by installing its successor, standard-nntplib, and it is still there. (venv) mailman@darni:~$ pip3.13 install standard-nntplib Requirement already satisfied: standard-nntplib in /usr/local/mailman/venv/lib/python3.13/site-packages (3.13.0) That used to work for 3.3.9. But the 3.3.10 version may have no verbiage to say that the nntlib is replaced by standard-nntplib Now I seem to have managed to hose my environment. (venv) mailman@darni:~$ mailman version Traceback (most recent call last): File "/usr/local/mailman/venv/bin/mailman", line 3, in <module> from mailman.bin.mailman import main File "/usr/local/mailman/venv/lib/python3.13/site-packages/mailman/bin/mailman.py", line 25, in <module> from mailman.core.initialize import initialize File "/usr/local/mailman/venv/lib/python3.13/site-packages/mailman/core/initialize.py", line 29, in <module> import mailman.config.config File "/usr/local/mailman/venv/lib/python3.13/site-packages/mailman/config/__init__.py", line 20, in <module> from mailman.config.config import Configuration File "/usr/local/mailman/venv/lib/python3.13/site-packages/mailman/config/config.py", line 32, in <module> from mailman.utilities.modules import call_name, expand_path File "/usr/local/mailman/venv/lib/python3.13/site-packages/mailman/utilities/modules.py", line 23, in <module> from pkg_resources import resource_filename, resource_listdir ModuleNotFoundError: No module named 'pkg_resources' What now? -- Written by Thomas Krichel http://openlib.org/home/krichel on his 22213th day.

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