Original version from BALUG:

https://wiki.sluug.org/mailman_2_-_mailman_3

Thanks!!

---

## Mailman 3

### Debian

* **Debian 10 “Buster”**

  * LTS EOL: 2024‑06‑30
  * First stable to support Mailman 3; last to support Mailman 2

* **balug-sf-lug-v2.balug.org (balug.org)**

  * `mailman3` startup script (as `list` user, `LANG=en_US.UTF-8`, `umask 022`)

    ```sh
    #!/bin/sh
    umask 022 &&
    unset LC_ALL &&
    LANG=en_US.UTF-8 export LANG &&
    case "$(id -n -u)" in
        list)
            umask 022 &&
            exec mailman "$@"
            ;;
        *)
            umask 022 &&
            exec sudo -u list \
            mailman "$@"
            ;;
    esac
    ```

* Typical commands:

  ```sh
  /usr/share/mailman3-web/manage.py            # help
  manage.py createsuperuser
  manage.py changepassword <login_name>
  ```

* **Databases** (SQLite examples):

  * `/var/lib/mailman3/data/mailman.db`
  * `/var/lib/dbconfig-common/sqlite3/mailman3-web/mailman3web.db`

  Backup command:

  ```sh
  sqlite3 /path/to/mailman3web.db \
    ".backup '/path/to/mailman3web.BACKUP.db'"
  ```

* Example list: `balug-test3@lists.balug.org`

  * Web UI:

    * Public: `https://lists.balug.org/mailman3/`
    * Admin: `https://lists.balug.org/mailman3/admin/`

### Archiving & Import Behavior

* Headers like `X-Archive`, `X-No-Archive` respected; conflicts result in no archive.

* Imported archives:

  * append to existing data
  * headers and bodies may be altered (To, CC headers stripped or changed, content-type altered)

* Archives stored in database tables like `hyperkitty_email` ([wiki.balug.org][1])

* Downloadable via `.mbox.gz`, e.g.:
  `https://lists.balug.org/mailman3/hyperkitty/list/…/export/…​.mbox.gz` ([wiki.balug.org][1])

* Email obfuscation:

  * GUI and downloaded archives may alter “@” to “(a)” inconsistently; actual DB data may be unaltered ([wiki.balug.org][1])

### Managing Messages & Lists

* Delete individual messages via admin UI or directly in DB (`hyperkitty_email`) ([wiki.balug.org][1])
* Rename lists and adjust archive and posting settings through Postorius UI ([wiki.balug.org][1])
* Prevent archiving while allowing posting via disabling “Active archivers” in settings&#x20;

### Migration Checklist

| Task                                  | test | admin | talk | announce |
| ------------------------------------- | :--: | :---: | :--: | :------: |
| lock old                              |   y  |   y   |   y  |     y    |
| handle pending                        |   y  |   y   |   y  |     y    |
| create/rename target                  |   y  |   y   |   y  |     y    |
| migrate config                        |   y  |   y   |   y  |     y    |
| migrate archive                       |   y  |   y   |   y  |     y    |
| index archive                         |   y  |   y   |   y  |     y    |
| archive \*.pck files                  |   y  |   y   |   y  |     y    |
| archive info pages                    |   y  |   y   |   y  |     y    |
| remove Mailman 2 list (keep archives) |   y  |   y   |   y  |     y    |
| update lists.balug.org site           |   y  |   y   |   y  |     y    |
| update links on balug.org             |   y  |   y   |   y  |     y    |
| set Mailman 2→3 redirects             |  ir  |   ir  |  ir  |    ir    |
| update Mailman 2 archive links        |   n  |   n   |   n  |     n    |
| customize templates                   |   i  |   i   |   i  |     i    |
| update monthly stats                  |   -  |   y   |   -  |     -    |

Legend:

* **y** = done
* **n** = not done
* **ir** = redirects are in place
* **i** = in progress

### Migration Procedure & Notes

1. Ensure Debian supports it (e.g., Buster → Bookworm).
2. Lock/suspend Mailman 2:

   * Remove or comment out aliases in `/etc/aliases` and run `newaliases` ([wiki.balug.org][1])
3. Create corresponding Mailman 3 lists via Postorius or CLI.
4. Import config:

   ```sh
   mailman import21 <list> /var/lib/mailman/lists/*/config.pck
   ```

   * Workaround: run as `list` user and reset `bounce_info` if import fails ([wiki.balug.org][1])
5. Import and index archives:

   ```sh
   manage.py hyperkitty_import -l <list> --since 1968 /var/lib/mailman/archives/private/*.mbox
   manage.py update_index_one_list <list>
   manage.py update_index -s 1970-01-01T00:00:00
   ```

   * Must be run as `www-data` on Debian ([wiki.balug.org][1])
6. Remove old Mailman 2 list:

   ```sh
   /usr/lib/mailman/bin/rmlist <list>
   ```

   * Old archives remain unless you use `-a` option ([wiki.balug.org][1])
7. Update site redirects, links, and stats reporting (e.g. cron scripts for monthly summaries).
8. Optional: mass-export/import user preferences, but user logins differ (per-list vs. per-account) ([wiki.balug.org][1])

### Feature & Configuration Mapping

* Delivery status, digest preferences, moderation options, and user settings generally map 1:1 from Mailman 2 to Mailman 3 (with some exceptions due to default settings or absence of certain flags) ([wiki.balug.org][1])
* Some template formatting quirks (e.g. line-wrapping at 70 chars). Use leading whitespace to avoid unwanted wrapping ([wiki.balug.org][1])
* Gravatar leakage issue fixed in HyperKitty ≥ 1.3.4; disable via `HYPERKITTY_ENABLE_GRAVATAR` in later versions ([wiki.balug.org][1])

---

Let me know if you'd like this as a downloadable Markdown file, cleaned up further, or reformatted to match another wiki syntax!

[1]: https://www.wiki.balug.org/wiki/doku.php?id=system%3Amailman3&utm_source=chatgpt.com "system:mailman3 [BALUG Wiki]"