diff --git a/flat-mcmc.cabal b/flat-mcmc.cabal
--- a/flat-mcmc.cabal
+++ b/flat-mcmc.cabal
@@ -1,5 +1,5 @@
 name:                flat-mcmc
-version:             1.5.0
+version:             1.5.1
 synopsis:            Painless general-purpose sampling.
 homepage:            https://github.com/jtobin/flat-mcmc
 license:             MIT
@@ -9,6 +9,7 @@
 category:            Math
 build-type:          Simple
 cabal-version:       >= 1.18
+tested-with:         GHC == 8.6.5
 description:
   flat-mcmc is a Haskell library for painless, efficient, general-purpose
   sampling from continuous distributions.
@@ -65,7 +66,7 @@
     , mcmc-types       >= 1.0.1 && < 2
     , monad-par        >= 0.3.4.7 && < 1
     , monad-par-extras >= 0.3.3 && < 1
-    , mwc-probability  >= 1.0.1 && < 2
+    , mwc-probability  >= 1.0.1 && < 3
     , pipes            >= 4     && < 5
     , primitive        >= 0.6   && < 1
     , text             >= 1.2   && < 2
diff --git a/lib/Numeric/MCMC/Flat.hs b/lib/Numeric/MCMC/Flat.hs
--- a/lib/Numeric/MCMC/Flat.hs
+++ b/lib/Numeric/MCMC/Flat.hs
@@ -48,7 +48,6 @@
 import Control.Monad.Par.Scheds.Sparks hiding (get)
 import Control.Monad.Primitive (PrimMonad, PrimState)
 import Control.Monad.Trans.State.Strict (get, put, execStateT)
-import Data.Monoid
 import Data.Sampling.Types as Sampling.Types hiding (Chain(..))
 import qualified Data.Text as T
 import qualified Data.Text.IO as T (putStrLn)