diff --git a/src/Handler/Utils/Submission.hs b/src/Handler/Utils/Submission.hs
index 8ce8df7e3..2713994ba 100644
--- a/src/Handler/Utils/Submission.hs
+++ b/src/Handler/Utils/Submission.hs
@@ -111,24 +111,7 @@ sinkSubmission sheetId userId mExists = do
             matchesUnderlying
               | not (null underlyingFiles) = all (~~ file) [ f | (Entity _ f, Entity _ sf) <- underlyingFiles ]
               | otherwise                  = False
-            undoneDeletion = any submissionFileIsDeletion [ sf | (_, Entity _ sf) <- collidingFiles
-                                                               ]
-
-            a /~ b = not $ a ~~ b
-
-            (~~) :: File -> File -> Bool
-            (~~) = (==)
-            -- The Eq Instance for File compares modification time exactly even
-            -- though zip archives have very limited accuracy and range regarding
-            -- timestamps.
-            -- We thus expect to replace files a little more often than is actually
-            -- necessary.
-            -- This was done on the premise that changes in file modification time
-            -- break file identity under upload and re-download.
-            --
-            -- Similarly the check whether the new version matches the underlying
-            -- file is arguably too agressive, marking files, differing only in
-            -- modification time, as modified.
+            undoneDeletion = any submissionFileIsDeletion [ sf | (_, Entity _ sf) <- collidingFiles ]
   
         when anyChanges $ do
           touchSubmission
@@ -179,6 +162,23 @@ sinkSubmission sheetId userId mExists = do
             , SubmissionRatingComment =. ratingComment
             ]
       where
+        a /~ b = not $ a ~~ b
+
+        (~~) :: File -> File -> Bool
+        (~~) a b
+          | isUpdate  = fileTitle a == fileTitle b && fileContent a == fileContent b
+          | otherwise = a == b
+        -- The Eq Instance for File compares modification time exactly even
+        -- though zip archives have very limited accuracy and range regarding
+        -- timestamps.
+        -- We thus expect to replace files a little more often than is actually
+        -- necessary.
+        -- This was done on the premise that changes in file modification time
+        -- break file identity under upload and re-download.
+        --
+        -- The check whether the new version matches the underlying file is
+        -- more lenient, considering only filename and -content.
+
         touchSubmission :: StateT SubmissionSinkState (YesodDB UniWorX) ()
         touchSubmission = do
           alreadyTouched <- gets $ getAny . sinkSubmissionTouched
diff --git a/stack.yaml b/stack.yaml
index a976d4ac2..c889ad49d 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -6,10 +6,6 @@ nix:
 extra-package-dbs: []
 packages:
 - .
-- location:
-    git: https://github.com/pngwjpgh/conduit-resumablesink.git
-    commit: ee0679dc31cdcedb2dad240b941262b9dc16f06d
-  extra-dep: true
 - location:
     git: https://github.com/pngwjpgh/zip-stream.git
     commit: 9272bbed000928d500febad1cdc98d1da29d399e
@@ -18,6 +14,7 @@ extra-deps:
 - colonnade-1.1.1
 - yesod-colonnade-1.1.0
 # - zip-stream-0.1.0.1
+- conduit-resumablesink-0.2
 - uuid-crypto-1.3.1.0
 - filepath-crypto-0.0.0.0
 - cryptoids-0.4.0.0
diff --git a/test/Handler/Utils/Zip/RatingSpec.hs b/test/Handler/Utils/Zip/RatingSpec.hs
deleted file mode 100644
index dc26958c4..000000000
--- a/test/Handler/Utils/Zip/RatingSpec.hs
+++ /dev/null
@@ -1,33 +0,0 @@
-{-# LANGUAGE NoImplicitPrelude #-}
-{-# LANGUAGE RecordWildCards #-}
-
-{-# OPTIONS_GHC -fno-warn-orphans #-}
-
-module Handler.Utils.Zip.RatingSpec where
-
-import TestImport
-
-import Handler.Utils.Zip.Rating
-
-import qualified Data.ByteString.Lazy as Lazy.ByteString
-
-import qualified Data.Text as Text
-
-import Database.Persist.Class
-import Database.Persist.Sql
-
-
-instance Arbitrary Rating where
-  arbitrary = do
-    ratingCourseName <- arbitrary
-    ratingSheetName <- arbitrary
-    ratingSubmissionId <- SubmissionKey . SqlBackendKey <$> arbitrary
-    ratingComment <- (fmap Text.strip <$> arbitrary) `suchThat` maybe True (not . Text.null)
-    ratingPoints <- arbitrary
-    return Rating{..}
-
-
-spec :: Spec
-spec = describe "Rating files" $ do
-  it "have compatible formatting/parsing" . property $ 
-    \rating@(Rating{..}) -> parseRating (Lazy.ByteString.toStrict $ formatRating rating) >>= (`shouldBe` (ratingPoints, ratingComment))