Software¶

Tip

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1. Client Requirements¶

Please note that, while Zammad being a web application, there’s some requirements for your clients. This ensures that Zammad works as expected.

1.1 Supported Browsers¶

Because Zammad is a web application, only an up-to-date browser is needed. The following browsers are supported in their latest stable version:

  • Firefox

  • Chrome (and Chromium-based)

  • Opera

  • Safari

This does not mean that Zammad will not work with other browsers or older versions, just that we do not test against or provide support for them.

The communication between client and server is based on web sockets. Some firewalls may filter these connections. This may lead to decreased browser performance.

1.2 Network Requirements¶

Zammad uses web sockets. Some application firewalls may filter these connections. This may lead to decreased browser performance. There’s a fallback to Ajax which causes a higher application server load and thus should be avoided. In case you’re having issues with field selection, you can activate the AJAX Mode for “Core Workflows” separately.

2. Server Requirements¶

If you want to install Zammad, you need the following software.

Note

Most of the software versions listed below (unless stated as specific version) are minimum requirements of Zammad. We strongly encourage you to use most current possible versions that are not end of life.

Docker and Kubernetes are shipping all dependencies and services by default!

Warning

Due to a known issue in OpenSSL 3.6.0, this version is not supported. In case your distro offers you 3.6.0 already, check if you can stay on a lower version or - when available - jump directly to a higher version.

2.1 Supported Distributions¶

Zammad provides binary packages for the most recent two stable / long-term-support releases of the supported Linux distributions, until they reach their end-of-life or until they can no longer provide the technical requirements for Zammad. Using of the latest supported stable / long-term-support version is generally recommended.

Below you can find all distributions Zammad provides packages for.

Supported operating systems for package installation¶

Distribution

Versions

CentOS / RHEL

9

Debian

11, 12 & 13

OpenSUSE / SLES

Leap 15.x / 15

Ubuntu

22.04 & 24.04

If you distribution is not listed, you can still install Zammad. For this you can either use Docker Compose or Kubernetes installation. We try to provide all current distributions that are supported by Packager.io. This means that we can’t always provide support for your favorite system.

Note

Upgrading your host operating system to a newer supported version?

Make sure to follow the installation guide for the new version and have a look at the host upgrade page, where you can find general steps how to do this.

2.2 Package Dependencies¶

The dependencies below need to be installed on your system. If you’re using the package installation method, these packages will automatically be installed with the Zammad-Package.

$ sudo apt install libimlib2

Note

libimlib2-dev or imlib2-devel are no longer required.
However: If you have to use bundle install for e.g. custom gems or development, you’ll need to install it!

2.3 Database Server¶

Zammad stores its content in a database. The supported database system is PostgreSQL 13 or newer. If no PostgreSQL server could be detected, it will be installed automatically during the package installation.

Note

If you use database connection pooling software like PgBouncer, make sure to use a pooling mode that is fully compatible with PostgreSQL. Typically this is called “session connection pooling”. Transaction-based connection pooling is not supported and may lead to errors during database migrations.

2.4 Reverse Proxy¶

In a typical web environment today, you use a reverse proxy to deliver the static content of your application. Only the “expensive” app required HTTP requests are forwarded to the application server.

The following reverse proxies are supported:

  • Nginx 1.3+

  • Apache 2.2+

Hint

Some configuration is required, please see Configure the Webserver.

2.5 Redis¶

Redis is required for realtime communication via web socket. Zammad requires Redis 6 or newer. It gets installed automatically (package) or is included in the stack (Docker Compose) with a working configuration. However, the installation and configuration is out of scope of this documentation. Please follow the official guides and ensure to set it up in a secure way.

Available environment variables for standard and Sentinel setups are briefly mentioned in the Redis Variables page.

2.6 Elasticsearch (optional)¶

Zammad uses Elasticsearch to:

  1. make the search faster,

  2. support advanced features like reports,

  3. search for content of email attachments.

This becomes increasingly important the higher the number of tickets in your system gets.

Warning

This dependency is optional but strongly recommended!

Zammad will work without it, but search performance will be degraded and the search will be very limited. We recommend using Elasticsearch, as it will boost the usage of Zammad greatly!

Zammad/Elasticsearch version compatibility¶

Zammad

Elasticsearch

7.0+

>= 7.8, < 10

5.2 - 6.5

>= 7.8, < 9

5.0 - 5.1

>= 7.8, < 8

4.0-4.1

>= 6.5, <= 7.12

3.4-3.6

>= 5.5, <= 7.9

3.3

>= 2.4, <=7.6

3.2

>= 2.4, <=7.5

3.1

>= 2.4, <=7.4

2.0-3.0

>= 2.4, <=5.6

An Elasticsearch plugin is required for version 7 or older to index the contents of email attachments: ingest-attachment. Starting with Elasticsearch 8, it is included by default.

Hint

You can override the Elasticsearch dependency for package installations (not recommended!)

It depends on your system how to manually override the Elasticsearch dependency (e.g. --force, --ignore-depends, --skip-broken); check your package manager’s manpage to find out.

2.7 Memcached¶

Zammad heavily relies on caching to improve performance. This cache can be stored in the file system without relying on externals services. However, this is only possible if all services of Zammad are running on the same file system!

In all other cases like deploying Zammad via containers (Docker or Kubernetes) or on separate cluster nodes, a Memcached service is required to store the cache and serve it to all Zammad instances. The Docker and Kubernetes stacks already include this service.

However, even local file system installations may benefit from Memcached’s performance improvements. You might want to have a look at our Environment Variables section too.

The installation and configuration is out of scope of this documentation. In case you have to install Memcached manually, please follow the official documentation of Memcached.

2.8 GnuPG (optional)¶

If you want to use the PGP integration for sending and receiving signed and encrypted emails, you need to install the GnuPG-Tool. Please have a look at the official GnuPG website.