diff --git a/dbt_meshify/storage/yaml_editors.py b/dbt_meshify/storage/yaml_editors.py
index b2fd0f2..3262518 100644
--- a/dbt_meshify/storage/yaml_editors.py
+++ b/dbt_meshify/storage/yaml_editors.py
@@ -136,7 +136,12 @@ def get_latest_yml_defined_version(self, model_yml: Dict[str, Any]):
         if no versions, returns 0
         """
         model_yml_versions = model_yml.get("versions", [])
-        return max([v.get("v") for v in model_yml_versions]) if model_yml_versions else 0
+        try:
+            return max([int(v.get("v")) for v in model_yml_versions]) if model_yml_versions else 0
+        except ValueError:
+            raise ValueError(
+                f"Version not an integer, can't increment version for {model_yml.get('name')}"
+            )
 
     def add_model_version_to_yml(
         self,
diff --git a/tests/fixtures.py b/tests/fixtures.py
index 1fd5948..437c065 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -252,3 +252,12 @@
       - v: 2
         defined_in: daves_model
 """
+
+model_yml_string_version = """
+models:
+  - name: shared_model
+    latest_version: john_olerud
+    description: "this is a test model"
+    versions:
+      - v: john_olerud
+"""
diff --git a/tests/integration/test_version_command.py b/tests/integration/test_version_command.py
index 776c84e..d02ad98 100644
--- a/tests/integration/test_version_command.py
+++ b/tests/integration/test_version_command.py
@@ -16,6 +16,7 @@
     expected_versioned_model_yml_no_yml,
     model_yml_increment_version,
     model_yml_no_col_no_version,
+    model_yml_string_version,
     shared_model_sql,
 )
 
@@ -119,3 +120,36 @@ def test_add_version_to_yml(start_yml, end_yml, start_files, expected_files, com
     yml_file.unlink()
     reset_model_files(["shared_model.sql"])
     assert actual == yaml.safe_load(end_yml)
+
+
+@pytest.mark.parametrize(
+    "start_yml,start_files,command_options",
+    [
+        (
+            model_yml_string_version,
+            ["shared_model.sql"],
+            [],
+        ),
+    ],
+    ids=["1"],
+)
+def test_add_version_to_invalid_yml(start_yml, start_files, command_options):
+    yml_file = proj_path / "models" / "_models.yml"
+    reset_model_files(start_files)
+    yml_file.parent.mkdir(parents=True, exist_ok=True)
+    runner = CliRunner()
+    # only create file if start_yml is not None
+    # in situations where models don't have a patch path, there isn't a yml file to read from
+    if start_yml:
+        yml_file.touch()
+        start_yml_content = yaml.safe_load(start_yml)
+        with open(yml_file, "w+") as f:
+            yaml.safe_dump(start_yml_content, f, sort_keys=False)
+    base_command = ["--select", "shared_model", "--project-path", proj_path_string]
+    base_command.extend(command_options)
+    result = runner.invoke(add_version, base_command, catch_exceptions=True)
+    assert result.exit_code == 1
+    assert "Version not an integer" in str(result.exception)
+    # reset the read path to the default in the logic
+    yml_file.unlink()
+    reset_model_files(["shared_model.sql"])