diff --git a/package.yaml b/package.yaml
index f340b2806..cfbb27a7e 100644
--- a/package.yaml
+++ b/package.yaml
@@ -93,6 +93,7 @@ dependencies:
   - connection
   - universe
   - universe-base
+  - universe-reverse-instances
   - random
   - random-shuffle
   - th-abstraction
diff --git a/src/Data/Universe/Instances/Reverse/Hashable.hs b/src/Data/Universe/Instances/Reverse/Hashable.hs
index 70b43c8f3..c9a3049c6 100644
--- a/src/Data/Universe/Instances/Reverse/Hashable.hs
+++ b/src/Data/Universe/Instances/Reverse/Hashable.hs
@@ -1,4 +1,4 @@
--- SPDX-FileCopyrightText: 2024 Stephan Barth <stephan.barth@uniworx.de>, 2022 Gregor Kleen <gregor.kleen@ifi.lmu.de>
+-- SPDX-FileCopyrightText: 2022-2024 Stephan Barth <stephan.barth@uniworx.de>, Gregor Kleen <gregor.kleen@ifi.lmu.de>
 --
 -- SPDX-License-Identifier: AGPL-3.0-or-later
 
@@ -12,8 +12,9 @@ import ClassyPrelude
 
 import Data.Universe
 
-instance (Eq b, Finite a) => Eq (a -> b) where
-  (==) f g = [ f k | k <- universeF ] == [ g k | k <- universeF ]
+-- is indirectly imported elsewhere and already provides instance (Eq b, Finite a) => Eq (a -> b) where
+import Data.Universe.Instances.Eq()
+
 
 instance (Hashable a, Hashable b, Finite a) => Hashable (a -> b) where
   hashWithSalt s f = s `hashWithSalt` [ (k, f k) | k <- universeF ]
diff --git a/src/Mail.hs b/src/Mail.hs
index 4f9ab00d6..a253273b8 100644
--- a/src/Mail.hs
+++ b/src/Mail.hs
@@ -208,6 +208,8 @@ _MailSmtpDataSet = to $ \MailSmtpData{..} -> none id
   , Set.null smtpRecipients
   ]
 
+--instance Eq (SelDateTimeFormat -> DateTimeFormat)
+
 
 data MailContext = MailContext
   { mcLanguages :: Languages
@@ -215,6 +217,8 @@ data MailContext = MailContext
   , mcCsvOptions :: CsvOptions
   } deriving (Eq, Ord, Read, Show, Generic)
 
+--deriving via (Data.Universe.Class.Finite) instance Eq MailContext
+
 deriveJSON defaultOptions
   { fieldLabelModifier = intercalate "-" . map toLower . drop 1 . splitCamel
   } ''MailContext