diff --git a/chart-unit.cabal b/chart-unit.cabal
--- a/chart-unit.cabal
+++ b/chart-unit.cabal
@@ -5,7 +5,7 @@
 -- hash: c39db1e3a55127346b3e41e1ba315b1d704563184f7b39b9a3885f64e76b4387
 
 name:           chart-unit
-version:        0.6.0.1
+version:        0.6.0.2
 synopsis:       Native haskell charts.
 description:    .
                 <<https://tonyday567.github.io/other/mainExample.svg>>
@@ -147,7 +147,7 @@
     , formatting
     , generic-lens-labels
     , lens
-    , mwc-probability
+    , mwc-probability >= 1.2.0 && < 2
     , mwc-random
     , numhask
     , numhask-histogram