You're reading the documentation for an older, but still supported, version of ROS 2. For information on the latest version, please have a look at Humble.

Testing with pre-release binaries

Many ROS packages are provided as pre-built binaries. Usually, you will get the released version of binaries when following Installation. There are also pre-released versions of binaries that are useful for testing before making an official release. This article describes several options if you would like to try out pre-released versions of ROS binaries.

Debian testing repository

When packages are released into a ROS distribution (using bloom), the buildfarm builds them into debian packages which are stored temporarily in the building apt repository. As dependent packages are rebuilt, an automatic process periodically synchronizes the packages in building to a secondary repository called ros-testing. ros-testing is intended as a soaking area where developers and bleeding-edge users may give the packages extra testing, before they are manually synced into the public ros repository from which users typically install packages.

Approximately every two weeks, the rosdistro’s release manager manually synchronizes the contents of ros-testing into the main ROS repository.

For Debian-based operating systems, you can install binary packages from the ros-testing repository.

Make sure you have a working ROS 2 installation from Debian packages (see Installation).
Edit (with sudo) the file /etc/apt/sources.list.d/ros2-latest.list and change ros2 with ros2-testing. For example, on Ubuntu Focal the contents should look like the following:
```
# deb http://packages.ros.org/ros2/ubuntu focal main
deb http://packages.ros.org/ros2-testing/ubuntu focal main
```
Update the apt index:
```
sudo apt update
```
You can now install individual packages from the testing repository, for example:
```
sudo apt install ros-foxy-my-just-released-package
```
Alternatively, you can move your entire ROS 2 installation to the testing repository:
```
sudo apt dist-upgrade
```
Once you are finished testing, you can switch back to the normal repository by changing back the contents of /etc/apt/sources.list.d/ros2-latest.list:
```
deb http://packages.ros.org/ros2/ubuntu focal main
# deb http://packages.ros.org/ros2-testing/ubuntu focal main
```
and doing an update and upgrade:
```
sudo apt update
sudo apt dist-upgrade
```