diff --git a/MANUAL.md b/MANUAL.md
index 0c4a887..ade9de4 100644
--- a/MANUAL.md
+++ b/MANUAL.md
@@ -37,8 +37,8 @@ credentials used elsewhere in deployments and applications.
   and `z3`.
 
 - `stemcell_os` - The operating system stemcell you want to deploy
-  on. (default: `ubuntu-xenial`)
-  
+  on. (default: `ubuntu-bionic`)
+
 - `stemcell_version` - The specific version of the stemcell you want
   to deploy on. (default: `latest`)
 
@@ -46,10 +46,10 @@ credentials used elsewhere in deployments and applications.
   names the availability set to deploy the Vault nodes across.
   This parameter does not have any effect on other platforms.
 
-- `auxiliary_vault` - If deploying a second Vault after the 
+- `auxiliary_vault` - If deploying a second Vault after the
   primary Genesis Vault was deployed. This prevents automatic
-  unsealing of the Vault after a deploy, as Genesis will attempt 
-  to unseal the new Vault with the seal keys of the primary 
+  unsealing of the Vault after a deploy, as Genesis will attempt
+  to unseal the new Vault with the seal keys of the primary
   Genesis Vault. Defaults to `false`.
 
 - `ui` - If true, the Vault Web UI will be turned on. Defaults to true.
diff --git a/manifests/vault.yml b/manifests/vault.yml
index bd8ad4e..d47628a 100644
--- a/manifests/vault.yml
+++ b/manifests/vault.yml
@@ -44,5 +44,5 @@ update:
 
 stemcells:
   - alias:   default
-    os:      (( grab params.stemcell_os      || "ubuntu-xenial" ))
+    os:      (( grab params.stemcell_os      || "ubuntu-bionic" ))
     version: (( grab params.stemcell_version || "latest"        ))
diff --git a/spec/results/azure.yml b/spec/results/azure.yml
index b943c39..4ba247b 100644
--- a/spec/results/azure.yml
+++ b/spec/results/azure.yml
@@ -45,7 +45,7 @@ releases:
   version: 0.3.2
 stemcells:
 - alias: default
-  os: ubuntu-xenial
+  os: ubuntu-bionic
   version: latest
 update:
   canaries: 1
diff --git a/spec/results/base.yml b/spec/results/base.yml
index e2dca47..03f7dfb 100644
--- a/spec/results/base.yml
+++ b/spec/results/base.yml
@@ -45,7 +45,7 @@ releases:
   version: 0.3.2
 stemcells:
 - alias: default
-  os: ubuntu-xenial
+  os: ubuntu-bionic
   version: latest
 update:
   canaries: 1