diff --git a/contrib/android/Readme.md b/contrib/android/Readme.md
index 9ecaebd26..a5a0b4d35 100644
--- a/contrib/android/Readme.md
+++ b/contrib/android/Readme.md
@@ -13,12 +13,7 @@ similar system.
 
 1. Install Docker
 
-    ```
-    $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
-    $ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
-    $ sudo apt-get update
-    $ sudo apt-get install -y docker-ce
-    ```
+    See `contrib/docker_notes.md`.
 
 2. Build binaries
 
diff --git a/contrib/build-linux/appimage/README.md b/contrib/build-linux/appimage/README.md
index 838777b87..7680aafc6 100644
--- a/contrib/build-linux/appimage/README.md
+++ b/contrib/build-linux/appimage/README.md
@@ -14,12 +14,7 @@ see [issue #5159](https://github.com/spesmilo/electrum/issues/5159).
 
 1. Install Docker
 
-    ```
-    $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
-    $ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
-    $ sudo apt-get update
-    $ sudo apt-get install -y docker-ce
-    ```
+    See `contrib/docker_notes.md`.
 
 2. Build binary
 
diff --git a/contrib/build-linux/sdist/README.md b/contrib/build-linux/sdist/README.md
index 2ff3ed011..96f8bb82b 100644
--- a/contrib/build-linux/sdist/README.md
+++ b/contrib/build-linux/sdist/README.md
@@ -9,12 +9,7 @@ similar system.
 
 1. Install Docker
 
-    ```
-    $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
-    $ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
-    $ sudo apt-get update
-    $ sudo apt-get install -y docker-ce
-    ```
+    See `contrib/docker_notes.md`.
 
 2. Build source tarball
 
diff --git a/contrib/build-wine/README.md b/contrib/build-wine/README.md
index 61fdf205d..617dd9b12 100644
--- a/contrib/build-wine/README.md
+++ b/contrib/build-wine/README.md
@@ -9,12 +9,7 @@ similar system.
 
 1. Install Docker
 
-    ```
-    $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
-    $ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
-    $ sudo apt-get update
-    $ sudo apt-get install -y docker-ce
-    ```
+    See `contrib/docker_notes.md`.
 
     Note: older versions of Docker might not work well
     (see [#6971](https://github.com/spesmilo/electrum/issues/6971)).
diff --git a/contrib/docker_notes.md b/contrib/docker_notes.md
new file mode 100644
index 000000000..e1ab3b8a7
--- /dev/null
+++ b/contrib/docker_notes.md
@@ -0,0 +1,21 @@
+# Notes about using Docker in the build scripts
+
+- To install Docker:
+
+    This assumes an Ubuntu (x86_64) host, but it should not be too hard to adapt to another similar system.
+
+    ```
+    $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
+    $ sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
+    $ sudo apt-get update
+    $ sudo apt-get install -y docker-ce
+    ```
+
+- To communicate with the docker daemon, the build scripts either need to be called via sudo,
+  or the unix user on the host system (e.g. the user you run as) needs to be
+  part of the `docker` group. i.e.:
+  ```
+  $ sudo usermod -aG docker ${USER}
+  ```
+  (and then reboot or similar for it to take effect)
+