diff --git a/ghc-typelits-presburger.cabal b/ghc-typelits-presburger.cabal
--- a/ghc-typelits-presburger.cabal
+++ b/ghc-typelits-presburger.cabal
@@ -1,5 +1,5 @@
 name:                ghc-typelits-presburger
-version:             0.2.0.2
+version:             0.2.0.3
 synopsis:            Presburger Arithmetic Solver for GHC Type-level natural numbers.
 description: 
   @ghc-typelits-presburger@ augments GHC type-system with Presburger Arithmetic Solver for Type-level natural numbers.
@@ -17,13 +17,13 @@
 build-type:          Simple
 -- extra-source-files:
 cabal-version:       >=1.10
-tested-with:         GHC == 8.0.2, GHC == 8.2.2
+tested-with:         GHC == 8.0.2, GHC == 8.2.2, GHC == 8.4.3
 
 flag examples
     Default: False
 
 library
-  ghc-options:         -Wall
+  ghc-options:         -Wall -Wno-dodgy-imports
   hs-source-dirs:      src
                      , presburger/src
   exposed-modules:     GHC.TypeLits.Presburger
@@ -51,7 +51,7 @@
                      , equational-reasoning
                      , singletons
   default-language:    Haskell2010
-  ghc-options:         -Wall
+  ghc-options:         -Wall -Wno-dodgy-imports -Wno-unused-imports
 
 source-repository head
   type:     git
diff --git a/src/GHC/TypeLits/Presburger.hs b/src/GHC/TypeLits/Presburger.hs
--- a/src/GHC/TypeLits/Presburger.hs
+++ b/src/GHC/TypeLits/Presburger.hs
@@ -1,5 +1,6 @@
-{-# LANGUAGE FlexibleContexts, MultiWayIf, OverloadedStrings, PatternGuards #-}
-{-# LANGUAGE RankNTypes, RecordWildCards, TupleSections                     #-}
+{-# LANGUAGE CPP, FlexibleContexts, MultiWayIf, OverloadedStrings      #-}
+{-# LANGUAGE PatternGuards, RankNTypes, RecordWildCards, TupleSections #-}
+{-# OPTIONS_GHC -Wno-unused-imports #-}
 module GHC.TypeLits.Presburger (plugin) where
 import GHC.Compat
 
@@ -144,7 +145,11 @@
   vmd <- lookupModule (mkModuleName "Data.Void") (fsLit "base")
   voidTyCon <- tcLookupTyCon =<< lookupOrig vmd (mkTcOcc "Void")
   singletons <- lookupModule (mkModuleName "Data.Singletons.Prelude.Ord") (fsLit "singletons")
+#if MIN_VERSION_singletons(2,4,1)
   typeLeqBoolTyCon_ <- tcLookupTyCon =<< lookupOrig singletons (mkTcOcc "<=")
+#else
+  typeLeqBoolTyCon_ <- tcLookupTyCon =<< lookupOrig singletons (mkTcOcc ":<=")
+#endif
   singCompareCon_ <- tcLookupTyCon =<< lookupOrig singletons (mkTcOcc "Compare")
   give MyEnv{..} act