diff --git a/app/aws/s3.py b/app/aws/s3.py
index d5acb69fd..a64be797c 100644
--- a/app/aws/s3.py
+++ b/app/aws/s3.py
@@ -91,7 +91,7 @@ def upload_letters_pdf(reference, crown, filedata):
         colour="C",
         crown="C" if crown else "N",
         date=now.strftime('%Y%m%d%H%M%S')
-    )
+    ).upper()
 
     utils_s3upload(
         filedata=filedata,
diff --git a/tests/app/aws/test_s3.py b/tests/app/aws/test_s3.py
index d144a29f0..e610560db 100644
--- a/tests/app/aws/test_s3.py
+++ b/tests/app/aws/test_s3.py
@@ -157,5 +157,5 @@ def test_upload_letters_pdf_calls_utils_s3upload_with_correct_args(
         filedata='some_data',
         region='eu-west-1',
         bucket_name='test-letters-pdf',
-        file_location='2017-12-04/NOTIFY.foo.D.2.C.{}.20171204150000.pdf'.format(expected_crown_text)
+        file_location='2017-12-04/NOTIFY.FOO.D.2.C.{}.20171204150000.PDF'.format(expected_crown_text)
     )