diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index b48c5f1643c3805a8a496a6fff07c98a0946d9a0..864401c706da93547bf0b7c52edc73861ca93e08 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -79,9 +79,9 @@ use it. This is a manual process for now. Follow these steps:
 1. Create a new VPS
 2. Run the following to install *only kubernetes* on the VPS:
    ```
-   $ python3 -m openappstack <cluster> install --install-kubernetes --no-install-openappstack
+   $ python3 -m openappstack <cluster> install
    ```
-3. Log into your machine and clean up the k3s server, then delete the cluster 
+3. Log into your machine and clean up the k3s server, then delete the cluster
    data:
    ```
    # Clean up running containers and firewall
@@ -96,7 +96,7 @@ use it. This is a manual process for now. Follow these steps:
    2. Set VPS to `-- not assigned --`
    3. Click 'make template'
    4. Choose "Linux Latest LTS" as the kernel
-   5. Choose OS type Debian 10
+   5. Choose OS type Debian 11 (bullseye)
    6. Remember the disk image ID that you can see in the current URL as `id=...`
    7. Click save
 6. Change the `--disk-image-id` argument in `.gitlab/ci_scripts/create_vps.sh`
diff --git a/docs/installation/create_cluster.rst b/docs/installation/create_cluster.rst
index 1e1ca1ef037ee66c00cd147a30a86b2aa133e333..181f7f8ff9b0f176e8b812876a17eb1ab7a85fb9 100644
--- a/docs/installation/create_cluster.rst
+++ b/docs/installation/create_cluster.rst
@@ -18,7 +18,7 @@ Prerequisites
 During these instructions, you are asked to create a VPS, or have a
 bare metal server ready. The server should meet these requirements:
 
-- Debian "buster" installed
+- Debian 11 (bullseye) installed
 - A public IP address
 - The ability to create DNS records for this IP
 - 6 cores and 12 GB of RAM
diff --git a/docs/installation/overview.rst b/docs/installation/overview.rst
index 883228ea00b0ad4c79bed2ef2bd8469ca098e88f..55aab1fe85d43eb6919783a58a4cd6bfd0373480 100644
--- a/docs/installation/overview.rst
+++ b/docs/installation/overview.rst
@@ -5,22 +5,22 @@ Installation overview
 =====================
 
 .. warning::
-  -  OpenAppStack is still under heavy development and is not ready for
+   - OpenAppStack is still under heavy development and is not ready for
      production use! We anticipate major changes and do not guarantee a
      data-preserving upgrade path from current installations. However, we
      encourage you to try OpenAppStack and ask you to `report all issues
      you encounter <https://openappstack.net/contact.html>`__.
-  -  When you install OpenAppStack on a server, the installation process
+   - When you install OpenAppStack on a server, the installation process
      will make some substantial changes to the server's configuration, so
      please do not use a server that functions as anything other than a
      testing ground.
 
- .. note::
-    You should also have a trusted machine to run the installer on, i.e. your
-    laptop. We call this the ``provisioning machine``.
-    All commands in these installation instructions need to be
-    run this provisioning machine that is *not* the server that will run
-    OpenAppStack, unless specified otherwise.
+.. note::
+   You should also have a trusted machine to run the installer on, i.e. your
+   laptop. We call this the ``provisioning machine``.
+   All commands in these installation instructions need to be
+   run this provisioning machine that is *not* the server that will run
+   OpenAppStack, unless specified otherwise.
 
 Setup
 =====
diff --git a/openappstack/cluster.py b/openappstack/cluster.py
index 9a45a001b7639ba904a50ec0ebb89f3bb454121a..6caf135c88fddfb22531a9fd946f4cf7bbfcbd8c 100644
--- a/openappstack/cluster.py
+++ b/openappstack/cluster.py
@@ -35,8 +35,8 @@ DEFAULT_REGION = 'ams1'
 DEFAULT_DISK_SIZE_GB = 30
 """Default amount of memory"""
 DEFAULT_MEMORY_SIZE_MB = 12288
-"""Default "image" (operating system): 19  =  Debian buster-x64 """
-DEFAULT_IMAGE = 19
+"""Default "image" (operating system): 19  =  Debian bullseye-x64 """
+DEFAULT_IMAGE = 26
 
 
 class Cluster: