diff --git a/tempest/lib/api_schema/response/compute/v2_13/server_groups.py b/tempest/lib/api_schema/response/compute/v2_13/server_groups.py
index 2b59e38..5cb4241 100644
--- a/tempest/lib/api_schema/response/compute/v2_13/server_groups.py
+++ b/tempest/lib/api_schema/response/compute/v2_13/server_groups.py
@@ -16,7 +16,9 @@
 
 from tempest.lib.api_schema.response.compute.v2_1 import server_groups
 
-
+# Compute microversion 2.13:
+# 1. New attributes in 'server_group' dict.
+#      'project_id', 'user_id'
 common_server_group = copy.deepcopy(server_groups.common_server_group)
 common_server_group['properties']['project_id'] = {'type': 'string'}
 common_server_group['properties']['user_id'] = {'type': 'string'}