diff --git a/core/grpc-haskell-core.cabal b/core/grpc-haskell-core.cabal
index 959cb70..61afb83 100644
--- a/core/grpc-haskell-core.cabal
+++ b/core/grpc-haskell-core.cabal
@@ -21,8 +21,8 @@ library
       base >=4.8 && <5.0
     , clock >=0.6.0 && <0.8.0
     , bytestring ==0.10.*
-    , stm == 2.4.*
-    , containers ==0.5.*
+    , stm >=2.4 && <2.6
+    , containers >=0.5 && <0.7
     , managed >= 1.0.0 && < 1.1
     , transformers
     , sorted-list >=0.1.6.1 && <=0.3
@@ -80,11 +80,11 @@ test-suite tests
     , bytestring ==0.10.*
     , unix
     , time
-    , async ==2.1.*
-    , tasty >= 0.11 && <0.12
-    , tasty-hunit >= 0.9 && <0.10
-    , tasty-quickcheck >= 0.8.4 && < 0.9
-    , containers ==0.5.*
+    , async >=2.1 && <2.3
+    , tasty >= 0.11
+    , tasty-hunit >= 0.9
+    , tasty-quickcheck >= 0.8.4
+    , containers >=0.5 && <0.7
     , managed >= 1.0.0 && < 1.1
     , pipes >=4.1 && <=4.4
     , proto3-suite
diff --git a/core/shell.nix b/core/shell.nix
new file mode 100644
index 0000000..b61179c
--- /dev/null
+++ b/core/shell.nix
@@ -0,0 +1 @@
+(import ../release.nix).grpc-haskell-core.env
diff --git a/core/src/Network/GRPC/LowLevel/Call.hs b/core/src/Network/GRPC/LowLevel/Call.hs
index 8f71bd0..9349ac9 100644
--- a/core/src/Network/GRPC/LowLevel/Call.hs
+++ b/core/src/Network/GRPC/LowLevel/Call.hs
@@ -20,7 +20,7 @@ import           Control.Exception                              (bracket)
 import           Data.ByteString                                (ByteString)
 import           Data.ByteString.Char8                          (pack)
 import           Data.List                                      (intersperse)
-import           Data.Monoid
+import           Data.Semigroup                                 ((<>))
 import           Data.String                                    (IsString)
 import           Foreign.Marshal.Alloc                          (free, malloc)
 import           Foreign.Ptr                                    (Ptr, nullPtr)
diff --git a/core/src/Network/GRPC/Unsafe/Metadata.chs b/core/src/Network/GRPC/Unsafe/Metadata.chs
index 9dd71a0..270ca0a 100644
--- a/core/src/Network/GRPC/Unsafe/Metadata.chs
+++ b/core/src/Network/GRPC/Unsafe/Metadata.chs
@@ -12,7 +12,7 @@ import Data.Function (on)
 import Data.ByteString (ByteString, useAsCString,
                         useAsCStringLen)
 import Data.List (sortBy, groupBy)
-import Data.Semigroup
+import Data.Semigroup (Semigroup((<>)))
 import qualified Data.SortedList as SL
 import qualified Data.Map.Strict as M
 import Data.Ord (comparing)
diff --git a/core/tests/UnsafeTests.hs b/core/tests/UnsafeTests.hs
index 936378a..eb8ba84 100644
--- a/core/tests/UnsafeTests.hs
+++ b/core/tests/UnsafeTests.hs
@@ -19,8 +19,8 @@ import           Network.GRPC.Unsafe.Security
 import           Network.GRPC.Unsafe.Slice
 import           Network.GRPC.Unsafe.Time
 import           System.Clock
-import           Test.QuickCheck.Gen             as QC
-import           Test.QuickCheck.Property        as QC
+import           Test.QuickCheck.Gen
+import qualified Test.QuickCheck.Property        as QC
 import           Test.Tasty
 import           Test.Tasty.HUnit                as HU (testCase, (@?=))
 import           Test.Tasty.QuickCheck           as QC
diff --git a/grpc-haskell.cabal b/grpc-haskell.cabal
index 98c2b17..5398e4e 100644
--- a/grpc-haskell.cabal
+++ b/grpc-haskell.cabal
@@ -53,7 +53,7 @@ executable hellos-server
       base >=4.8 && <5.0
       , async
       , bytestring == 0.10.*
-      , containers ==0.5.*
+      , containers >=0.5 && <0.7
       , grpc-haskell
       , grpc-haskell-core
       , proto3-suite
@@ -73,7 +73,7 @@ executable hellos-client
       base >=4.8 && <5.0
       , async
       , bytestring == 0.10.*
-      , containers ==0.5.*
+      , containers >=0.5 && <0.7
       , grpc-haskell
       , grpc-haskell-core
       , proto3-suite
@@ -93,7 +93,7 @@ executable echo-server
       base >=4.8 && <5.0
       , async
       , bytestring == 0.10.*
-      , containers ==0.5.*
+      , containers >=0.5 && <0.7
       , grpc-haskell
       , grpc-haskell-core
       , optparse-generic
@@ -117,7 +117,7 @@ executable arithmetic-server
       base >=4.8 && <5.0
       , async
       , bytestring == 0.10.*
-      , containers ==0.5.*
+      , containers >=0.5 && <0.7
       , grpc-haskell
       , grpc-haskell-core
       , optparse-generic
@@ -140,7 +140,7 @@ executable arithmetic-client
       base >=4.8 && <5.0
       , async
       , bytestring == 0.10.*
-      , containers ==0.5.*
+      , containers >=0.5 && <0.7
       , grpc-haskell
       , grpc-haskell-core
       , optparse-generic
@@ -163,7 +163,7 @@ executable echo-client
       base >=4.8 && <5.0
       , async
       , bytestring == 0.10.*
-      , containers ==0.5.*
+      , containers >=0.5 && <0.7
       , grpc-haskell
       , grpc-haskell-core
       , optparse-generic
@@ -189,10 +189,10 @@ test-suite tests
     , unix
     , time
     , async
-    , tasty >= 0.11 && <0.12
-    , tasty-hunit >= 0.9 && <0.10
-    , tasty-quickcheck >= 0.8.4 && < 0.9
-    , containers ==0.5.*
+    , tasty >= 0.11
+    , tasty-hunit >= 0.9
+    , tasty-quickcheck >= 0.8.4
+    , containers >=0.5 && <0.7
     , managed >= 1.0.0 && < 1.1
     , pipes >=4.1 && <=4.4
     , proto3-suite
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..39b5c83
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1 @@
+(import ./release.nix).grpc-haskell.env