diff --git a/README.md b/README.md
index fa976105..1840bba8 100644
--- a/README.md
+++ b/README.md
@@ -48,6 +48,7 @@ At the moment, only source installation is supported. Use Ubuntu Focal.
 
     ```
     export IGNITION_VERSION=fortress
+    export GZ_VERSION=fortress
     ```
 
 1. Install ROS dependencies
diff --git a/buoy_all.yaml b/buoy_all.yaml
index d6020fcd..63e7ea06 100644
--- a/buoy_all.yaml
+++ b/buoy_all.yaml
@@ -17,3 +17,7 @@ repositories:
     type: git
     url: https://github.com/osrf/ros_ign
     version: galactic
+  sdformat_urdf:
+    type: git
+    url: https://github.com/ros/sdformat_urdf
+    version: galactic
diff --git a/docker/buoy/Dockerfile b/docker/buoy/Dockerfile
index 6894c096..339093f3 100644
--- a/docker/buoy/Dockerfile
+++ b/docker/buoy/Dockerfile
@@ -9,6 +9,7 @@ RUN apt update \
 
 # Using non-official Gazebo + ROS combination, set it explicitly
 ENV IGNITION_VERSION fortress
+ENV GZ_VERSION fortress
 
 # Create project directory and import packages
 RUN mkdir -p /tmp/buoy_ws/src \