diff --git a/aern2-mp.cabal b/aern2-mp.cabal
--- a/aern2-mp.cabal
+++ b/aern2-mp.cabal
@@ -3,11 +3,9 @@
 -- This file has been generated from package.yaml by hpack version 0.34.4.
 --
 -- see: https://github.com/sol/hpack
---
--- hash: f380106cebd760457afe30f95f96a4613a687aa0d3f908c17172376defe10224
 
 name:           aern2-mp
-version:        0.2.5.0
+version:        0.2.6.0
 synopsis:       Multi-precision ball (interval) arithmetic
 description:    Please see the README on GitHub at <https://github.com/michalkonecny/aern2/#readme>
 category:       Math
@@ -91,7 +89,7 @@
     , deepseq
     , hspec
     , integer-logarithms
-    , mixed-types-num >=0.5.5
+    , mixed-types-num >=0.5.7
     , reflection
     , regex-tdfa
     , template-haskell
@@ -131,7 +129,7 @@
     , deepseq
     , hspec
     , integer-logarithms
-    , mixed-types-num >=0.5.5
+    , mixed-types-num >=0.5.7
     , reflection
     , regex-tdfa
     , template-haskell
diff --git a/src/AERN2/MP/Ball/Type.hs b/src/AERN2/MP/Ball/Type.hs
--- a/src/AERN2/MP/Ball/Type.hs
+++ b/src/AERN2/MP/Ball/Type.hs
@@ -99,6 +99,8 @@
     showAC NoInformation = "(oo)"
     showAC ac = " ~2^(" ++ show (negate $ fromAccuracy ac) ++ ")"
     
+instance CanTestIsIntegerType MPBall -- False by default
+
 -- instance CanTestValid MPBall where
 --   isValid = isFinite
 
diff --git a/src/AERN2/MP/ErrorBound.hs b/src/AERN2/MP/ErrorBound.hs
--- a/src/AERN2/MP/ErrorBound.hs
+++ b/src/AERN2/MP/ErrorBound.hs
@@ -29,8 +29,6 @@
 
 -- import Data.Convertible
 
-import Data.Ratio (numerator)
-
 import Math.NumberTheory.Logarithms (integerLog2)
 
 import AERN2.MP.Precision
@@ -228,6 +226,6 @@
         | otherwise =
           do
           (s :: Integer) <- arbitrary
-          let resultR = ((abs s) `P.mod` (numerator $ 2^35))/(2^32)
+          let resultR = ((abs s) `P.mod` (2^35))/(2^32)
           let result = convert resultR
           return result
diff --git a/src/AERN2/MP/WithCurrentPrec/Type.hs b/src/AERN2/MP/WithCurrentPrec/Type.hs
--- a/src/AERN2/MP/WithCurrentPrec/Type.hs
+++ b/src/AERN2/MP/WithCurrentPrec/Type.hs
@@ -60,6 +60,7 @@
     deriving (Show)
 
 deriving instance (CanTakeErrors NumErrors t) => (CanTakeErrors NumErrors (WithCurrentPrec t p))
+deriving instance (CanTestIsIntegerType t) => (CanTestIsIntegerType (WithCurrentPrec t p))
 
 runWithPrec :: Precision -> (forall n. (KnownNat n) => WithCurrentPrec t n) -> t
 runWithPrec p (wfp :: (forall n. (KnownNat n) => WithCurrentPrec t n)) =