diff --git a/client-haskell/src/Icepeak/Client.hs b/client-haskell/src/Icepeak/Client.hs
index c741a58..1842f78 100644
--- a/client-haskell/src/Icepeak/Client.hs
+++ b/client-haskell/src/Icepeak/Client.hs
@@ -43,7 +43,6 @@ import Control.Retry (RetryPolicyM, recovering)
 import Data.Aeson (ToJSON)
 import Data.ByteString (ByteString)
 import Data.Foldable (toList)
-import Data.Semigroup ((<>))
 import Data.Text (Text)
 import Data.Word (Word16)
 
diff --git a/client-haskell/stack.yaml b/client-haskell/stack.yaml
index da1e086..7506c4b 100644
--- a/client-haskell/stack.yaml
+++ b/client-haskell/stack.yaml
@@ -1,4 +1,4 @@
-resolver: lts-19.17
+resolver: lts-19.32
 
 # Note: This section will be ignored by stack, on non-NixOS systems.
 # It can be explicitly enabled on non-NixOS systems by passing --nix.
diff --git a/nix/sources.json b/nix/sources.json
index f274193..06cd22f 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -5,10 +5,10 @@
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "80fc83ad314fe701766ee66ac8286307d65b39e3",
-        "sha256": "0axxkwpkxy2c45acm257l510p3kbc7vbfxlddz78q5bvvr5l70rc",
+        "rev": "72d8853228c9758820c39b8659415b6d89279493",
+        "sha256": "10r5zh0052apd90riimaly2xc9d4w5p9g81s9nhjk12kirf6ihcs",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/80fc83ad314fe701766ee66ac8286307d65b39e3.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/72d8853228c9758820c39b8659415b6d89279493.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }
diff --git a/server/app/Icepeak/Main.hs b/server/app/Icepeak/Main.hs
index 0483ad5..0712e0d 100644
--- a/server/app/Icepeak/Main.hs
+++ b/server/app/Icepeak/Main.hs
@@ -5,7 +5,6 @@ module Main (main) where
 import Control.Exception (fromException, catch, handle, AsyncException, SomeException)
 import Control.Monad (forM, void, when)
 import Data.Foldable (forM_)
-import Data.Semigroup ((<>))
 import Options.Applicative (execParser)
 import System.Environment (getEnvironment)
 import System.IO (BufferMode (..), hSetBuffering, stdout)
diff --git a/server/app/IcepeakTokenGen/Main.hs b/server/app/IcepeakTokenGen/Main.hs
index 7f7eb6d..8eddce0 100644
--- a/server/app/IcepeakTokenGen/Main.hs
+++ b/server/app/IcepeakTokenGen/Main.hs
@@ -1,7 +1,6 @@
 {-# LANGUAGE OverloadedStrings #-}
 module Main where
 
-import           Data.Semigroup      ((<>))
 import qualified Data.Text           as Text
 import qualified Data.Text.IO        as Text
 import           Options.Applicative
diff --git a/server/package.yaml b/server/package.yaml
index b4adc2e..c7e750e 100644
--- a/server/package.yaml
+++ b/server/package.yaml
@@ -16,7 +16,7 @@ ghc-options:
 dependencies:
 - aeson                             >= 1.4.6 && < 2.1
 - async                             >= 2.2.2 && < 2.3
-- base                              >= 4.12.0 && < 4.16
+- base                              >= 4.15.0 && < 4.16
 - bytestring                        >= 0.10.8 && < 0.11
 - containers                        >= 0.6.0 && < 0.7
 - directory                         >= 1.3.3 && < 1.4
@@ -26,7 +26,7 @@ dependencies:
 - monad-logger                      >= 0.3.31 && < 0.4
 - mtl                               >= 2.2.2 && < 2.3
 - network                           >= 2.8.0 && < 3.2
-- optparse-applicative              >= 0.15.0 && < 0.17
+- optparse-applicative              >= 0.16.0 && < 0.17
 - prometheus-client                 >= 1.0.0 && < 1.2
 - prometheus-metrics-ghc            >= 1.0.0 && < 1.1
 - random                            >= 1.1 && < 1.3
diff --git a/server/src/Config.hs b/server/src/Config.hs
index 65c0383..4b79194 100644
--- a/server/src/Config.hs
+++ b/server/src/Config.hs
@@ -6,9 +6,9 @@ module Config (
   configInfo,
 ) where
 
-import Control.Applicative (optional)
-import Data.Semigroup ((<>))
-import Options.Applicative
+import Options.Applicative ((<|>), auto, eitherReader, flag, flag', fullDesc, header, help, helper,
+                            info, long, metavar, option, optional, strOption, switch, value,
+                            Parser, ParserInfo, ReadM)
 import qualified Network.Wai.Handler.Warp as Warp
 import qualified Text.Read as Read
 import qualified Data.Char as Char
diff --git a/server/src/MetricsServer.hs b/server/src/MetricsServer.hs
index 53cf8a2..2420345 100644
--- a/server/src/MetricsServer.hs
+++ b/server/src/MetricsServer.hs
@@ -2,7 +2,6 @@
 module MetricsServer where
 
 import           Data.Function                     ((&))
-import           Data.Monoid                       ((<>))
 import qualified Data.Text                         as Text
 import qualified Network.Wai.Handler.Warp          as Warp
 import qualified Network.Wai.Middleware.Prometheus as PrometheusWai
diff --git a/server/src/Server.hs b/server/src/Server.hs
index e624534..527ade0 100644
--- a/server/src/Server.hs
+++ b/server/src/Server.hs
@@ -5,7 +5,6 @@ module Server
 )
 where
 
-import Data.Semigroup ((<>))
 import Data.Text (pack)
 
 import Network.Wai (Application)
diff --git a/server/stack.yaml b/server/stack.yaml
index c824ef8..4730371 100644
--- a/server/stack.yaml
+++ b/server/stack.yaml
@@ -1,4 +1,4 @@
-resolver: lts-19.17
+resolver: lts-19.32
 
 extra-deps:
   - raven-haskell-0.1.4.1