diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index dd9a9463b3c4..96bf7cb70fdb 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -1470,32 +1470,36 @@ self: super: {
   pandoc-types = doDistribute self.pandoc-types_1_21;
   rfc5051 = doDistribute self.rfc5051_0_2;
 
+  # Upstream forgot to change the Cabal version bounds in the test suite.
+  # See: https://github.com/jaspervdj/stylish-haskell/pull/297
+  # Will be fixed whenever they next bump the version number
+  stylish-haskell = appendPatch super.stylish-haskell (pkgs.fetchpatch {
+    url = "https://github.com/jaspervdj/stylish-haskell/commit/9550aa1cd177aa6fe271d075177109d66a79e67f.patch";
+    sha256 = "159jr80k40hdq5gpqfjknqx6vj2licx1l0f57l5r3k4264lnxjdb";
+  });
   # INSERT NEW OVERRIDES ABOVE THIS LINE
 
 } // (let
-  inherit (self) hls-ghcide;
+  inherit (self) hls-ghcide hls-brittany;
   hlsScopeOverride = self: super: {
     # haskell-language-server uses its own fork of ghcide
     # Test disabled: it seems to freeze (is it just that it takes a long time ?)
-    ghcide = hls-ghcide;
+    ghcide = dontCheck hls-ghcide;
     # we are faster than stack here
     hie-bios = dontCheck super.hie-bios_0_7_1;
     lsp-test = dontCheck super.lsp-test_0_11_0_5;
     # fourmolu can‘t compile with an older aeson
     aeson = dontCheck super.aeson_1_5_2_0;
     # brittany has an aeson upper bound of 1.5
-    brittany = doJailbreak super.brittany;
+    brittany = hls-brittany;
+    data-tree-print = doJailbreak super.data-tree-print;
+    ghc-exactprint = dontCheck super.ghc-exactprint_0_6_3_2;
   };
   in {
     # jailbreaking for hie-bios 0.7.0 (upstream PR: https://github.com/haskell/haskell-language-server/pull/357)
     haskell-language-server = dontCheck (doJailbreak (super.haskell-language-server.overrideScope hlsScopeOverride));
-    hls-ghcide = appendPatch (dontCheck (super.hls-ghcide.overrideScope hlsScopeOverride))
-      (pkgs.fetchpatch {
-        # This patch loosens the hie-bios upper bound.
-        # It is already merged into upstream and won‘t be needed for ghcide 0.4.0
-        url = "https://github.com/haskell/ghcide/commit/3e1b3620948870a4da8808ca0c0897fbd3ecad16.patch";
-        sha256 = "1jwn7jgi740x6wwv1k0mz9d4z0b9p3mzs54pdg4nfq0h2v7zxchz";
-      });
-    fourmolu = super.fourmolu.overrideScope hlsScopeOverride;
+    hls-ghcide = dontCheck (super.hls-ghcide.overrideScope hlsScopeOverride);
+    hls-brittany = dontCheck (super.hls-brittany.overrideScope hlsScopeOverride);
+    fourmolu = dontCheck (super.fourmolu.overrideScope hlsScopeOverride);
   }
 )  // import ./configuration-tensorflow.nix {inherit pkgs haskellLib;} self super
diff --git a/pkgs/development/haskell-modules/non-hackage-packages.nix b/pkgs/development/haskell-modules/non-hackage-packages.nix
index dc6dbe650614..7cd4547d9042 100644
--- a/pkgs/development/haskell-modules/non-hackage-packages.nix
+++ b/pkgs/development/haskell-modules/non-hackage-packages.nix
@@ -23,6 +23,7 @@ self: super: {
   # both are auto-generated by pkgs/development/tools/haskell/haskell-language-server/update.sh
   haskell-language-server = self.callPackage ../tools/haskell/haskell-language-server { };
   hls-ghcide = self.callPackage ../tools/haskell/haskell-language-server/hls-ghcide.nix { };
+  hls-brittany = self.callPackage ../tools/haskell/haskell-language-server/hls-brittany.nix { };
 
   # cabal2nix --revision <rev> https://github.com/hasura/ci-info-hs.git
   ci-info = self.callPackage ../misc/haskell/hasura/ci-info {};
diff --git a/pkgs/development/tools/haskell/haskell-language-server/default.nix b/pkgs/development/tools/haskell/haskell-language-server/default.nix
index c29ed6ce07ef..10cfa57f9147 100644
--- a/pkgs/development/tools/haskell/haskell-language-server/default.nix
+++ b/pkgs/development/tools/haskell/haskell-language-server/default.nix
@@ -14,8 +14,8 @@ mkDerivation {
   version = "0.4.0.0";
   src = fetchgit {
     url = "https://github.com/haskell/haskell-language-server.git";
-    sha256 = "157bsq6i824bl6krw7znp0byd8ibaqsq7mfwnkl741dmrflsxpa9";
-    rev = "cb861b878ae01911b066182ff0d8080050c3b2d6";
+    sha256 = "1fh9k9b3880m6ql4i10yn2yanskk9xhrakrrddqvainhcf2ik8hl";
+    rev = "c4576992f443a9abe48ffcfa0e2d2b9bce15d7ae";
     fetchSubmodules = true;
   };
   isLibrary = true;
diff --git a/pkgs/development/tools/haskell/haskell-language-server/hls-brittany.nix b/pkgs/development/tools/haskell/haskell-language-server/hls-brittany.nix
new file mode 100644
index 000000000000..0519cf42dd8c
--- /dev/null
+++ b/pkgs/development/tools/haskell/haskell-language-server/hls-brittany.nix
@@ -0,0 +1,36 @@
+{ mkDerivation, aeson, base, butcher, bytestring, cmdargs
+, containers, czipwith, data-tree-print, deepseq, directory, extra
+, fetchgit, filepath, ghc, ghc-boot-th, ghc-exactprint, ghc-paths
+, hspec, monad-memo, mtl, multistate, parsec, pretty, random, safe
+, semigroups, stdenv, strict, syb, text, transformers, uniplate
+, unsafe, yaml
+}:
+mkDerivation {
+  pname = "brittany";
+  version = "0.12.1.1";
+  src = fetchgit {
+    url = "https://github.com/bubba/brittany";
+    sha256 = "1rkk09f8750qykrmkqfqbh44dbx1p8aq1caznxxlw8zqfvx39cxl";
+    rev = "c59655f10d5ad295c2481537fc8abf0a297d9d1c";
+    fetchSubmodules = true;
+  };
+  isLibrary = true;
+  isExecutable = true;
+  libraryHaskellDepends = [
+    aeson base butcher bytestring cmdargs containers czipwith
+    data-tree-print deepseq directory extra filepath ghc ghc-boot-th
+    ghc-exactprint ghc-paths monad-memo mtl multistate pretty random
+    safe semigroups strict syb text transformers uniplate unsafe yaml
+  ];
+  executableHaskellDepends = [ base ];
+  testHaskellDepends = [
+    aeson base butcher bytestring cmdargs containers czipwith
+    data-tree-print deepseq directory extra filepath ghc ghc-boot-th
+    ghc-exactprint ghc-paths hspec monad-memo mtl multistate parsec
+    pretty safe semigroups strict syb text transformers uniplate unsafe
+    yaml
+  ];
+  homepage = "https://github.com/lspitzner/brittany/";
+  description = "Haskell source code formatter";
+  license = stdenv.lib.licenses.agpl3;
+}
diff --git a/pkgs/development/tools/haskell/haskell-language-server/hls-ghcide.nix b/pkgs/development/tools/haskell/haskell-language-server/hls-ghcide.nix
index c6a9b31fb738..af38312a3616 100644
--- a/pkgs/development/tools/haskell/haskell-language-server/hls-ghcide.nix
+++ b/pkgs/development/tools/haskell/haskell-language-server/hls-ghcide.nix
@@ -5,21 +5,20 @@
 , ghc-boot-th, ghc-check, ghc-paths, ghc-typelits-knownnat, gitrev
 , haddock-library, hashable, haskell-lsp, haskell-lsp-types
 , hie-bios, hslogger, lens, lsp-test, mtl, network-uri
-, opentelemetry, optparse-applicative, prettyprinter
-, prettyprinter-ansi-terminal, process, QuickCheck
-, quickcheck-instances, regex-tdfa, rope-utf16-splay, safe
-, safe-exceptions, shake, sorted-list, stdenv, stm, syb, tasty
-, tasty-expected-failure, tasty-hunit, tasty-quickcheck
-, tasty-rerun, text, time, transformers, unix, unordered-containers
-, utf8-string, yaml
+, optparse-applicative, prettyprinter, prettyprinter-ansi-terminal
+, process, QuickCheck, quickcheck-instances, regex-tdfa
+, rope-utf16-splay, safe, safe-exceptions, shake, sorted-list
+, stdenv, stm, syb, tasty, tasty-expected-failure, tasty-hunit
+, tasty-quickcheck, tasty-rerun, text, time, transformers, unix
+, unordered-containers, utf8-string, yaml
 }:
 mkDerivation {
   pname = "ghcide";
-  version = "0.2.0";
+  version = "0.3.0";
   src = fetchgit {
     url = "https://github.com/haskell/ghcide";
-    sha256 = "1zq7ngaak8il91a309rl51dghzasnk4m2sm3av6d93cyqyra1hfc";
-    rev = "078e3d3c0d319f83841ccbcdc60ff5f0e243f6be";
+    sha256 = "15v3g3i5v0xbq50lfvl4bv3rx01nixiqx02sddqi5lj2idgmg24g";
+    rev = "96cf8c53d0bdc16d3d2cd0559b74962593ce6dc5";
     fetchSubmodules = true;
   };
   isLibrary = true;
@@ -29,10 +28,10 @@ mkDerivation {
     containers cryptohash-sha1 data-default deepseq directory extra
     filepath fuzzy ghc ghc-boot ghc-boot-th ghc-check ghc-paths
     haddock-library hashable haskell-lsp haskell-lsp-types hie-bios
-    hslogger mtl network-uri opentelemetry prettyprinter
-    prettyprinter-ansi-terminal regex-tdfa rope-utf16-splay safe
-    safe-exceptions shake sorted-list stm syb text time transformers
-    unix unordered-containers utf8-string
+    hslogger mtl network-uri prettyprinter prettyprinter-ansi-terminal
+    regex-tdfa rope-utf16-splay safe safe-exceptions shake sorted-list
+    stm syb text time transformers unix unordered-containers
+    utf8-string
   ];
   executableHaskellDepends = [
     aeson base bytestring containers data-default directory extra
@@ -52,7 +51,7 @@ mkDerivation {
     aeson base Chart Chart-diagrams diagrams diagrams-svg directory
     extra filepath shake text yaml
   ];
-  homepage = "https://github.com/digital-asset/ghcide#readme";
+  homepage = "https://github.com/haskell/ghcide#readme";
   description = "The core of an IDE";
   license = stdenv.lib.licenses.asl20;
 }
diff --git a/pkgs/development/tools/haskell/haskell-language-server/update.sh b/pkgs/development/tools/haskell/haskell-language-server/update.sh
index 2f2741e9a49a..fd22a80126d9 100755
--- a/pkgs/development/tools/haskell/haskell-language-server/update.sh
+++ b/pkgs/development/tools/haskell/haskell-language-server/update.sh
@@ -7,6 +7,8 @@
 # Note that you should always try building haskell-language-server after updating it here, since
 # some of the overrides in pkgs/development/haskell/configuration-nix.nix may
 # need to be updated/changed.
+#
+# Remember to split out different updates into multiple commits
 
 set -eo pipefail
 
@@ -31,6 +33,22 @@ echo "Running cabal2nix and outputting to ${ghcide_derivation_file}..."
 
 cabal2nix --revision "$ghcide_new_version" "https://github.com/haskell/ghcide" > "$ghcide_derivation_file"
 
+# ===========================
+# HLS maintainer's Brittany fork
+# ===========================
+
+# brittany derivation created with cabal2nix.
+brittany_derivation_file="${script_dir}/hls-brittany.nix"
+
+# This is the current revision of the brittany fork in Nixpkgs.
+brittany_old_version="$(sed -En 's/.*\bversion = "(.*?)".*/\1/p' "$brittany_derivation_file")"
+
+brittany_new_version=$(curl --silent "https://api.github.com/repos/bubba/brittany/commits/ghc-8.10.1" | jq '.sha' --raw-output)
+
+echo "Updating haskell-language-server's brittany from old version $brittany_old_version to new version $brittany_new_version."
+echo "Running cabal2nix and outputting to ${brittany_derivation_file}..."
+
+cabal2nix --revision "$brittany_new_version" "https://github.com/bubba/brittany" > "$brittany_derivation_file"
 
 # ===========================
 # HLS