diff --git a/lib/refrepo/valid/input/schemas/schema-node.yaml b/lib/refrepo/valid/input/schemas/schema-node.yaml
index ec8c98a7d68609ce38f672e20757f43d9ebf7007..1342b88335a4731e1fc67d79726a7e9e4efd9717 100644
--- a/lib/refrepo/valid/input/schemas/schema-node.yaml
+++ b/lib/refrepo/valid/input/schemas/schema-node.yaml
@@ -6,7 +6,7 @@ architecture:
   nb_threads: integer
   cpu_core_numbering: string
 bios:
-  release_date: string
+  release_date: optional_string
   vendor: optional  # optional_string or null
   version: required  # string ?
   configuration: