diff --git a/Graphs/PureGraphPrune.hs b/Graphs/PureGraphPrune.hs
--- a/Graphs/PureGraphPrune.hs
+++ b/Graphs/PureGraphPrune.hs
@@ -168,7 +168,7 @@
 nChildren :: Ord nodeInfo => PureGraph nodeInfo arcInfo -> nodeInfo -> Int
 nChildren (PureGraph fm :: PureGraph nodeInfo arcInfo) nf =
    let
-      fm1 = Map.foldWithKey
+      fm1 = Map.foldrWithKey
          (\ a nodeData fm0 ->
             let
                parents1 = parentNodes nodeData
diff --git a/Setup.hs b/Setup.hs
deleted file mode 100644
--- a/Setup.hs
+++ /dev/null
@@ -1,2 +0,0 @@
-import Distribution.Simple
-main = defaultMain
diff --git a/uni-graphs.cabal b/uni-graphs.cabal
--- a/uni-graphs.cabal
+++ b/uni-graphs.cabal
@@ -1,5 +1,5 @@
 name:           uni-graphs
-version:        2.2.1.1
+version:        2.2.1.2
 build-type:     Simple
 license:        LGPL
 license-file:   LICENSE
@@ -9,8 +9,8 @@
 category:       GUI
 synopsis:       Graphs
 description:    Graphs toolkit
-cabal-version:  >= 1.4
-Tested-With:    GHC==7.10.3, GHC==8.4.3
+cabal-version:  >= 1.10
+Tested-With:    GHC==8.8.4
 
 flag debug
   description: add debug traces
@@ -32,3 +32,5 @@
     cpp-options: -DDEBUG
 
   ghc-options: -fwarn-unused-imports -fno-warn-warnings-deprecations
+
+  default-language: Haskell2010