diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -206,7 +206,7 @@
 
 ```
 stack build
-mpiexec stack exec versionn
+mpiexec stack exec version
 mpiexec -n 3 stack exec example1
 mpiexec -n 3 stack exec example2
 ```
diff --git a/lib/Control/Distributed/MPI.chs b/lib/Control/Distributed/MPI.chs
--- a/lib/Control/Distributed/MPI.chs
+++ b/lib/Control/Distributed/MPI.chs
@@ -254,7 +254,7 @@
 import Foreign
 import Foreign.C.String
 import Foreign.C.Types
-import GHC.Arr (indexError)
+import GHC.Err (errorWithoutStackTrace)
 import GHC.Generics hiding (Datatype, from, to)
 import System.IO.Unsafe (unsafePerformIO)
 
@@ -471,6 +471,15 @@
 
 instance Show Rank where
   showsPrec p (Rank r) = showsPrec p r
+
+{-# NOINLINE indexError #-}
+indexError :: Show a => (a,a) -> a -> String -> b
+indexError rng i tp =
+  errorWithoutStackTrace
+  (showString "Ix{" . showString tp . showString "}.index: Index " .
+    showParen True (showsPrec 0 i) .
+    showString " out of range " $
+    showParen True (showsPrec 0 rng) "")
 
 instance Ix Rank where
   range (Rank rmin, Rank rmax) = Rank <$> [rmin..rmax]
diff --git a/mpi-hs.cabal b/mpi-hs.cabal
--- a/mpi-hs.cabal
+++ b/mpi-hs.cabal
@@ -1,13 +1,13 @@
 cabal-version: 1.12
 
--- This file has been generated from package.yaml by hpack version 0.31.2.
+-- This file has been generated from package.yaml by hpack version 0.33.0.
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: f2cf4257a32103f47022facfd6a094ae6a3b6fc48338053b6afeb7fc7ec6dc5f
+-- hash: 76678d6f4a9e2157f8bfa828de7335f0b79031fb15e4c6d6676f41c88cff1632
 
 name:           mpi-hs
-version:        0.7.1.2
+version:        0.7.2.0
 synopsis:       MPI bindings for Haskell
 description:    MPI (the [Message Passinag Interface](https://www.mpi-forum.org)) is
                 a widely used standard for distributed-memory programming on HPC
@@ -124,9 +124,9 @@
         mpich
   if flag(mpich-macports)
     include-dirs:
-        /opt/local/include/mpich-gcc9
+        /opt/local/include/mpich-mp
     extra-lib-dirs:
-        /opt/local/lib/mpich-gcc9
+        /opt/local/lib/mpich-mp
     extra-libraries:
         mpi
   if flag(mpich-ubuntu)
@@ -197,9 +197,9 @@
         mpich
   if flag(mpich-macports)
     include-dirs:
-        /opt/local/include/mpich-gcc9
+        /opt/local/include/mpich-mp
     extra-lib-dirs:
-        /opt/local/lib/mpich-gcc9
+        /opt/local/lib/mpich-mp
     extra-libraries:
         mpi
   if flag(mpich-ubuntu)
@@ -270,9 +270,9 @@
         mpich
   if flag(mpich-macports)
     include-dirs:
-        /opt/local/include/mpich-gcc9
+        /opt/local/include/mpich-mp
     extra-lib-dirs:
-        /opt/local/lib/mpich-gcc9
+        /opt/local/lib/mpich-mp
     extra-libraries:
         mpi
   if flag(mpich-ubuntu)
@@ -343,9 +343,9 @@
         mpich
   if flag(mpich-macports)
     include-dirs:
-        /opt/local/include/mpich-gcc9
+        /opt/local/include/mpich-mp
     extra-lib-dirs:
-        /opt/local/lib/mpich-gcc9
+        /opt/local/lib/mpich-mp
     extra-libraries:
         mpi
   if flag(mpich-ubuntu)
@@ -418,9 +418,9 @@
         mpich
   if flag(mpich-macports)
     include-dirs:
-        /opt/local/include/mpich-gcc9
+        /opt/local/include/mpich-mp
     extra-lib-dirs:
-        /opt/local/lib/mpich-gcc9
+        /opt/local/lib/mpich-mp
     extra-libraries:
         mpi
   if flag(mpich-ubuntu)
@@ -492,9 +492,9 @@
         mpich
   if flag(mpich-macports)
     include-dirs:
-        /opt/local/include/mpich-gcc9
+        /opt/local/include/mpich-mp
     extra-lib-dirs:
-        /opt/local/lib/mpich-gcc9
+        /opt/local/lib/mpich-mp
     extra-libraries:
         mpi
   if flag(mpich-ubuntu)
diff --git a/package.yaml b/package.yaml
--- a/package.yaml
+++ b/package.yaml
@@ -1,5 +1,5 @@
 name: mpi-hs
-version: '0.7.1.2'
+version: '0.7.2.0'
 github: "eschnett/mpi-hs"
 license: Apache-2.0
 author: "Erik Schnetter <schnetter@gmail.com>"
@@ -104,9 +104,9 @@
       - mpich
   - condition: flag(mpich-macports)
     include-dirs:
-      - /opt/local/include/mpich-gcc9
+      - /opt/local/include/mpich-mp
     extra-lib-dirs:
-      - /opt/local/lib/mpich-gcc9
+      - /opt/local/lib/mpich-mp
     extra-libraries:
       - mpi
   - condition: flag(mpich-ubuntu)
diff --git a/stack.yaml b/stack.yaml
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,6 +1,9 @@
 # Resolver to choose a 'specific' stackage snapshot or a compiler version.
-resolver: lts-15.8
-# resolver: nightly-2020-03-24
+# resolver: lts-14.27
+# resolver: lts-15.3
+# resolver: lts-15.16
+resolver: lts-16.3
+# resolver: nightly-2020-06-29
 
 # User packages to be built.
 packages:
diff --git a/stack.yaml.lock b/stack.yaml.lock
--- a/stack.yaml.lock
+++ b/stack.yaml.lock
@@ -6,7 +6,7 @@
 packages: []
 snapshots:
 - completed:
-    size: 492015
-    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/15/8.yaml
-    sha256: 926bc3d70249dd0ba05277ff00943c0addb35b627cb641752669e7cf771310d0
-  original: lts-15.8
+    size: 531696
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/16/3.yaml
+    sha256: 65e3a94c65ad07fa1913649e3f1e36c4af51bf528a5d9fd217bdc1b46d0477cc
+  original: lts-16.3