diff --git a/app/models/submission.rb b/app/models/submission.rb
index 3d0c40c9..6136c09c 100644
--- a/app/models/submission.rb
+++ b/app/models/submission.rb
@@ -9,7 +9,7 @@ class Submission < ApplicationRecord
               remoteSubmit].freeze
   FILENAME_URL_PLACEHOLDER = '{filename}'
   MAX_COMMENTS_ON_RECOMMENDED_RFC = 5
-  OLDEST_RFC_TO_SHOW = 1.months
+  OLDEST_RFC_TO_SHOW = 1.month
 
   belongs_to :exercise
   belongs_to :study_group, optional: true