diff --git a/src/spiffworkflow_backend/services/git_service.py b/src/spiffworkflow_backend/services/git_service.py
index 15fab72e..aa3f9142 100644
--- a/src/spiffworkflow_backend/services/git_service.py
+++ b/src/spiffworkflow_backend/services/git_service.py
@@ -25,7 +25,7 @@ class GitService:
     @staticmethod
     def get_instance_file_contents_for_revision(
         process_model: ProcessModelInfo, revision: str
-    ) -> str:
+    ) -> bytes:
         """Get_instance_file_contents_for_revision."""
         bpmn_spec_absolute_dir = current_app.config["BPMN_SPEC_ABSOLUTE_DIR"]
         process_model_relative_path = FileSystemService.process_model_relative_path(
@@ -37,4 +37,4 @@ class GitService:
         # git show 78ae5eb:category_number_one/script-task/script-task.bpmn
         file_contents: str = os.popen(shell_command).read()[:-1]  # noqa: S605
         assert file_contents  # noqa: S101
-        return file_contents
+        return file_contents.encode('utf-8')