diff --git a/Numeric/MCMC/Hamiltonian.hs b/Numeric/MCMC/Hamiltonian.hs
--- a/Numeric/MCMC/Hamiltonian.hs
+++ b/Numeric/MCMC/Hamiltonian.hs
@@ -38,7 +38,6 @@
 import Control.Lens hiding (index)
 import Control.Monad (replicateM)
 import Control.Monad.Codensity (lowerCodensity)
-import Control.Monad.IO.Class (MonadIO, liftIO)
 import Control.Monad.Primitive (PrimState, PrimMonad)
 import Control.Monad.Trans.State.Strict hiding (state)
 import qualified Data.Foldable as Foldable (sum)
diff --git a/hasty-hamiltonian.cabal b/hasty-hamiltonian.cabal
--- a/hasty-hamiltonian.cabal
+++ b/hasty-hamiltonian.cabal
@@ -1,5 +1,5 @@
 name:                hasty-hamiltonian
-version:             1.3.2
+version:             1.3.3
 synopsis:            Speedy traversal through parameter space.
 homepage:            http://github.com/jtobin/hasty-hamiltonian
 license:             MIT
@@ -8,6 +8,7 @@
 maintainer:          jared@jtobin.ca
 category:            Numeric
 build-type:          Simple
+tested-with:         GHC == 8.2.2, GHC == 8.8.3
 cabal-version:       >= 1.10
 Description:
   Gradient-based traversal through parameter space.