This document provides information for creators of binary NZBGet packages.

Branches and releases

New features and fixes are added to NZBGet on daily basis. The actual source code can be obtained via source control repository as explained in Building development version. This most actual version is called development version (short devel or develop) or git version. Development code may contain serious bugs and is therefore not recommended for average users.

Implementing of one feature may take several days or even weeks. A short test of functionality is then performed on several platforms. If the program seems to work fine a new testing release is made available for public. Testing releases are provided from Download page. Testing releases are good for real use and are recommended for experienced users familiar with NZBGet. Testing releases may have serious bugs as well but this happen rare.

When all features planned for a new program version are implemented and several testing releases were published and no serious bugs were reported since the latest testing version a new program version is made available for public as stable release. Stable releases usually don’t have serious bugs and are recommended for new users as well for users who don’t have much time for frequent updates and are not ready to confront with possible bugs.

There are two main copies of source code in the code repository - develop and master. In the terms of source code tool “git” they are called branches. The current development is made in develop-branch. The testing releases are also produced from that branch. Stable releases are made from master-branch. That code branch always represents the latest stable code. Before creating a new stable release the changes made since the last stable are copied from develop-branch into master-branch. If a hotfix for the latest stable is required the fix is made in the master-branch and then a new stable release is created.

Having two branches - one for testing (develop) and another for stable (master) - ensures that code changes made in the development code of the new version do not flow into stable version before they thoroughly tested.

The recommended way of obtaining source code of stable and testing versions is Download page or Release archive.

Summary: there are three kinds of NZBGet releases:

  • Stable - recommended for new users and for users not having much time for possible error handling;
  • Testing - recommended for experienced users familiar with NZBGet;
  • Development - actual source code of NZBGet. Not recommended for average users.

What version to use for packaging

It’s recommended to always provide stable version. Providing a separate package for testing version would be nice too. Making publicly available packages of development versions is not recommended and should be avoided.

Automatic updates

Since NZBGet is written in C++ it is necessary to compile the program before it can be run. Compilation process is different on different platforms and is even more complex if a cross compiling is involved, which is an usual case when using the program on low power devices. For these reasons it’s not possible to offer an update function, which would download the latest sources and compile them automatically.

What is possible however is that the program could install already compiled binary package automatically. For end users the update process is automated but it relies on work made by package maintainer.

The maintainer needs to compile new version of NZBGet and make it available via Internet. When user starts auto-update function the program uses a special configuration file (provided along with installed package) to retrieve information about availability of new binary packages. If new version was found user can install it. For installation NZBGet calls an update-script, which is again written and provided by package maintainer. The script then downloads and installs new version and restarts NZBGet.

Package information file

For update check and installation of updates NZBGet requires:

  • web-link to update information file containing information about binary packages available for download and installation;
  • path to update-script, which is executed when user clicks on Install-button. These information must be provided in the file package-info.json located in webui-directory. The file must be installed with NZBGet.

Package information file:

  NZBGet.PackageInfo = {
  "update-info-link": "",
  "update-info-script": "/usr/local/bin/",
  "install-script": "/usr/local/bin/"


  • update-info-link - Link to update information file. See later.
  • update-info-script - Path to locally installed script file, which provides content of update information file. See later.
  • install-script - Path to locally installed script file, which installs new versions.

Information about available versions is provided in form of update information file. There are two ways to pass it to NZBGet:

  • The file can be put on web. In this case a link to the file must be put into field update-info-link of package information file;
  • The file can be generated by a locally installed script. In this case field update-info-script points to that script.

Only one of fields update-info-link or update-info-script must be present in the package information file.

Update information file

Example content of update information file:

  NZBGet.UpdateInfo = {
  "stable-version": "11.0",
  "stable-package-info": "",
  "testing-version": "12.0-testing-r920",
  "testing-package-info": "",
  "devel-version": "12.0-testing-r950",
  "devel-package-info": ""


  • stable-version, testing-version, devel-version - Version numbers of packages available for installation.
  • stable-package-info, testing-package-info, devel-package-info - Web-links to pages with information about packages, installations tips or any other useful info.

In the example all three milestone versions are provided but it’s not required to provide all of them. For example, if only stable version is available the file would look like this:

  NZBGet.UpdateInfo = {
  "stable-version": "11.0",
  "stable-package-info": ""

As you can see the update information file doesn’t provide download links to packages. NZBGet doesn’t download binary package nor install it. That’s a responsibility of update script, which knows where to get new version.

Update information script

One of a possible way to distribute NZBGet is to put it into a repository for binary packages and install it then from that repository. Example: optware repository.

In this case information about available binary packages and their versions can be obtained directly from package repository. This eliminates the need for hosting of update information file. Instead a special script file must be provided with NZBGet which then extracts version information from package repository and pass it to NZBGet.

TODO: provide more info and examples for of update information script

Process flow

To bring all pieces together:

  • User clicks on button Check for updates;
  • NZBGet loads file package-info.json from webui-directory;
    • If the file doesn’t exist a message Automatic updates are not configured for your platform is displayed;
  • NZBGet reads field update-info-link from package-info.json;
  • If field update-info-link exists NZBGet downloads update information file from the link;
  • If field update-info-link doesn’t exist, NZBGet reads field update-info-script and executes the script;
    • update-info-script checks availability of NZBGet versions and generates update information file;
  • NZBGet loads content of update information file and checks version numbers against installed version;
  • If newer version is available an Install-button appears;
  • User clicks on Install-button;
  • NZBGet executes script pointed by field install-script in package-info.json;
  • Install-script downloads new version, terminates NZBGet, installs new version, starts NZBGet;
    • During installation web-interface shows messages printed by install-script until NZBGet is terminated;
    • After that web-interface waits for NZBGet to start again;
    • If NZBGet was started successfully, web-interface reloads the page presenting new version to user.

Install script

The install script takes care of updating NZBGet to a newer version. The script must download and install the new version. The same script is called for installing stable, testing and development versions (if defined in update information file). The information about what of these version was chosen by user is passed in environment variable NZBUP_BRANCH. A process-id of NZBGet is passed in NZBUP_PROCESSID.

All NZBGet configuration options are also passed to script using env-vars with prefix NZBOP_. The variable names are written in UPPER CASE. For Example option ParRepair is passed as environment variable NZBOP_PARREPAIR. The dots in option names are replaced with underscores, for example NZBOP_SERVER1_HOST. For options with predefined possible values (yes/no, etc.) the values are passed always in lower case.

Example install script:##

  echo "Installing ${NZBUP_BRANCH}"
  echo "Downloading new version...";
  # wget 
  echo "Downloading new version...OK";
  echo "[ERROR] Something did go wrong (example error message)"
  echo "Extracting...";
  sleep 2;
  echo "Extracting...OK";
  echo "Stopping NZBGet...";
  # make a pause after printing the last message, which nzbget can receve from the script
  sleep 1;
  # in this demo we just wait 5 seconds
  # you should instead check if process with id "NZBUP_PROCESSID" still exist
  sleep 5;
  # after that point the message are not printed in nzbget web-interface anymore
  echo "Starting NZBGet...";

Real world examples

Automatic updates are implemented in: