diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,2 +1,3 @@
 0.0.0.2: Broken release, don't use
 0.1.0.0: Changed versions of dependencies, changed "data" to "newtype"
+0.1.1.0: Changed versions of dependencies
diff --git a/CheckCFGAmbiguity.hs b/CheckCFGAmbiguity.hs
--- a/CheckCFGAmbiguity.hs
+++ b/CheckCFGAmbiguity.hs
@@ -31,7 +31,6 @@
 import qualified Data.Set
 import Control.Monad.ST(runST)
 import Data.STRef(newSTRef, readSTRef, writeSTRef)
-import Data.Foldable(for_)
 import Data.Maybe(fromJust, catMaybes)
 import Data.List(find)
 import Data.Functor((<&>))
@@ -63,7 +62,7 @@
   nts = map fst g;
   g2 = g <&> \(nn, prod) -> (nn, prod <&> \symb -> if elem symb nts then N symb else T symb);
   g3 = sortBy (\(a, _) (b, _) -> compare a b) g2;
-  g4 = groupBy (\(a, _) (b, _) -> a == b) g3 <&> \gr -> (fst $ head gr, map snd gr);
+  g4 = groupBy (\(a, _) (b, _) -> a == b) g3 <&> \gr -> (fst $ (gr !! 0), map snd gr); -- "gr !! 0" instead of "head gr" to silence ghc warnings
 } in Data.Map.fromList g4
 conv g = fromJust $ toGrammar $ conv2 g -- We know that fromJust will not fail
 :}
diff --git a/check-cfg-ambiguity.cabal b/check-cfg-ambiguity.cabal
--- a/check-cfg-ambiguity.cabal
+++ b/check-cfg-ambiguity.cabal
@@ -1,6 +1,6 @@
 cabal-version:             3.0
 name:                      check-cfg-ambiguity
-version:                   0.1.0.0
+version:                   0.1.1.0
 synopsis:                  Checks context free grammar for ambiguity using brute force up to given limit
 description:               Checks context free grammar for ambiguity using brute force up to given limit.
 
@@ -27,8 +27,8 @@
   -- base 4.13 removed Monad.fail, so "before base 4.13 there was nothing"
   build-depends:
     -- CI-BOUNDS-BEGIN
-    base >= 4.13.0.0 && <= 4.17.0.0,
-    containers >= 0.6.2.1 && <= 0.6.6
+    base >= 4.13.0.0 && <= 4.19.1.0,
+    containers >= 0.6.2.1 && <= 0.6.8
     -- CI-BOUNDS-END
   default-language: Haskell2010
   ghc-options: -Wall -Wincomplete-patterns -Wincomplete-uni-patterns -Wmissing-export-lists -Wredundant-constraints -Wcompat -Wincomplete-record-updates -Wpartial-fields -Wunused-type-patterns -Wimplicit-lift
@@ -46,5 +46,5 @@
   type: exitcode-stdio-1.0
   ghc-options: -threaded
   main-is: doctests.hs
-  build-depends: base, doctest == 0.20.1, QuickCheck == 2.14.2
+  build-depends: base, doctest == 0.22.2, QuickCheck == 2.15.0.1
   default-language: Haskell2010