diff --git a/stackinator/schema.py b/stackinator/schema.py
index 0f6379d6..90849d9a 100644
--- a/stackinator/schema.py
+++ b/stackinator/schema.py
@@ -45,7 +45,7 @@ def py2yaml(data, indent):
 
 # load recipe yaml schema
 config_schema = json.load(open(prefix / "schema/config.json"))
-config_validator = validator(config_schema)
+config_validator = extend_with_default(jsonschema.Draft201909Validator)(config_schema)
 compilers_schema = json.load(open(prefix / "schema/compilers.json"))
 compilers_validator = validator(compilers_schema)
 environments_schema = json.load(open(prefix / "schema/environments.json"))
diff --git a/stackinator/schema/config.json b/stackinator/schema/config.json
index 49fae9b4..99d7a2b8 100644
--- a/stackinator/schema/config.json
+++ b/stackinator/schema/config.json
@@ -1,9 +1,9 @@
 {
-    "$schema": "http://json-schema.org/draft-07/schema#",
+    "$schema": "http://json-schema.org/draft-2019-09/schema#",
     "title": "Schema for Spack Stack config.yaml recipe file",
     "type" : "object",
-    "additionalProperties": false,
-    "required": ["name", "spack"],
+    "unevaluatedProperties": false,
+    "required": ["name"],
     "properties" : {
         "name" : {
             "type": "string"
@@ -12,38 +12,6 @@
             "type" : "string",
             "default" : "/user-environment"
         },
-        "spack" : {
-            "type" : "object",
-            "additionalProperties": false,
-            "properties" : {
-                "repo": {
-                    "type": "string"
-                },
-                "commit": {
-                    "oneOf": [
-                        {"type" : "string"},
-                        {"type" : "null"}
-                    ],
-                    "default": null
-                },
-                "packages" : {
-                    "type" : "object",
-                    "additionalProperties": false,
-                    "properties" : {
-                        "repo": {
-                            "type": "string"
-                        },
-                        "commit": {
-                            "oneOf": [
-                                {"type" : "string"},
-                                {"type" : "null"}
-                            ],
-                            "default": null
-                        }
-                    }
-                }
-            }
-        },
         "mirror" : {
             "type" : "object",
             "additionalProperties": false,
@@ -75,7 +43,87 @@
         },
         "version" : {
             "type": "number",
-            "default": 1
+            "default": 1,
+            "minimum": 1,
+            "maximum": 2
+        }
+    },
+    "allOf": [
+      {
+        "if": {
+          "required": ["version"],
+          "properties": {
+            "version": {"const": 2 }
+          }
+        },
+        "then": {
+          "required": ["spack"],
+          "properties": {
+            "spack": {
+              "$ref": "#/$defs/git-repo",
+              "unevaluatedProperties": false,
+              "required": ["packages"],
+              "properties": {
+                "packages": {
+                  "$ref": "#/$defs/git-repo",
+                  "unevaluatedProperties": false
+                }
+              }
+            }
+          }
+        }
+      },
+      {
+        "if": {
+          "oneOf": [
+            {
+              "not": {
+                "required": ["version"]
+              }
+            },
+            {
+              "required": ["version"],
+              "properties": {
+                "version": {"const": 1 }
+              }
+            }
+          ]
+        },
+        "then": {
+          "required": ["spack"],
+          "properties": {
+            "spack": {
+              "$ref": "#/$defs/git-repo",
+              "unevaluatedProperties": false
+            }
+          }
+        }
+      },
+      {
+        "if": {
+          "not": { "properties": { "version": { "minimum": 1, "maximum": 2} } }
+        },
+        "then": {
+          "properties": { "spack": {} }
+        }
+      }
+    ],
+    "$defs": {
+      "git-repo": {
+        "type" : "object",
+        "required": ["repo"],
+        "properties" : {
+          "repo": {
+            "type": "string"
+          },
+          "commit": {
+            "oneOf": [
+                {"type" : "string"},
+                {"type" : "null"}
+            ],
+            "default": null
+          }
         }
+      }
     }
 }
diff --git a/unittests/test_schema.py b/unittests/test_schema.py
index 9bc03264..4ba0e937 100644
--- a/unittests/test_schema.py
+++ b/unittests/test_schema.py
@@ -40,7 +40,8 @@ def test_config_yaml(yaml_path):
     # test that the defaults are set as expected
     with open(yaml_path / "config.defaults.yaml") as fid:
         raw = yaml.load(fid, Loader=yaml.Loader)
-        schema.validator(schema.config_schema).validate(raw)
+        schema.config_validator.validate(raw)
+        assert raw["version"] == 1
         assert raw["store"] == "/user-environment"
         assert raw["spack"]["commit"] is None
         assert raw["modules"] == True  # noqa: E712
@@ -49,34 +50,45 @@ def test_config_yaml(yaml_path):
 
     with open(yaml_path / "config.full.yaml") as fid:
         raw = yaml.load(fid, Loader=yaml.Loader)
-        schema.validator(schema.config_schema).validate(raw)
+        schema.config_validator.validate(raw)
+        assert raw["version"] == 1
         assert raw["store"] == "/alternative-point"
         assert raw["spack"]["commit"] == "6408b51"
         assert raw["modules"] == False  # noqa: E712
         assert raw["mirror"] == {"enable": True, "key": "/home/bob/veryprivate.key"}
         assert raw["description"] == "a really useful environment"
 
+    with open(yaml_path / "config.defaults.v2.yaml") as fid:
+        raw = yaml.load(fid, Loader=yaml.Loader)
+        schema.config_validator.validate(raw)
+        assert raw["store"] == "/user-environment"
+        assert raw["spack"]["commit"] is None
+        assert raw["spack"]["packages"]["commit"] is None
+        assert raw["modules"] == True  # noqa: E712
+        assert raw["mirror"] == {"enable": True, "key": None}
+        assert raw["description"] is None
+
 
 def test_recipe_config_yaml(recipe_paths):
     # validate the config.yaml in the test recipes
     for p in recipe_paths:
         with open(p / "config.yaml") as fid:
             raw = yaml.load(fid, Loader=yaml.Loader)
-            schema.validator(schema.config_schema).validate(raw)
+            schema.config_validator.validate(raw)
 
 
 def test_compilers_yaml(yaml_path):
     # test that the defaults are set as expected
     with open(yaml_path / "compilers.defaults.yaml") as fid:
         raw = yaml.load(fid, Loader=yaml.Loader)
-        schema.validator(schema.compilers_schema).validate(raw)
+        schema.compilers_validator.validate(raw)
         assert raw["bootstrap"] == {"spec": "gcc@11"}
         assert raw["gcc"] == {"specs": ["gcc@10.2"]}
         assert raw["llvm"] is None
 
     with open(yaml_path / "compilers.full.yaml") as fid:
         raw = yaml.load(fid, Loader=yaml.Loader)
-        schema.validator(schema.compilers_schema).validate(raw)
+        schema.compilers_validator.validate(raw)
         assert raw["bootstrap"]["spec"] == "gcc@11"
         assert raw["gcc"] == {"specs": ["gcc@11", "gcc@10.2", "gcc@9.3.0"]}
         assert raw["llvm"] == {
@@ -90,13 +102,13 @@ def test_recipe_compilers_yaml(recipe_paths):
     for p in recipe_paths:
         with open(p / "compilers.yaml") as fid:
             raw = yaml.load(fid, Loader=yaml.Loader)
-            schema.validator(schema.compilers_schema).validate(raw)
+            schema.compilers_validator.validate(raw)
 
 
 def test_environments_yaml(yaml_path):
     with open(yaml_path / "environments.full.yaml") as fid:
         raw = yaml.load(fid, Loader=yaml.Loader)
-        schema.validator(schema.environments_schema).validate(raw)
+        schema.environments_validator.validate(raw)
 
         # the defaults-env does not set fields
         # test that they have been set to the defaults correctly
@@ -145,7 +157,7 @@ def test_environments_yaml(yaml_path):
             jsonschema.exceptions.ValidationError,
             match=r"Additional properties are not allowed \('providers' was unexpected",
         ):
-            schema.validator(schema.environments_schema).validate(raw)
+            schema.environments_validator.validate(raw)
 
 
 def test_recipe_environments_yaml(recipe_paths):
@@ -153,4 +165,4 @@ def test_recipe_environments_yaml(recipe_paths):
     for p in recipe_paths:
         with open(p / "environments.yaml") as fid:
             raw = yaml.load(fid, Loader=yaml.Loader)
-            schema.validator(schema.environments_schema).validate(raw)
+            schema.environments_validator.validate(raw)
diff --git a/unittests/yaml/config.defaults.v2.yaml b/unittests/yaml/config.defaults.v2.yaml
new file mode 100644
index 00000000..9720dcf0
--- /dev/null
+++ b/unittests/yaml/config.defaults.v2.yaml
@@ -0,0 +1,13 @@
+version: 2
+name: cuda-env
+# store: /user-environment
+spack:
+    repo: https://github.com/spack/spack.git
+    # commit: None
+    packages:
+      repo: https://github.com/spack/spack-packages.git
+      # commit: None
+# mirror:
+    # key: None
+    # enable: True
+# modules: True