diff --git a/pkgs/development/compilers/elm/default.nix b/pkgs/development/compilers/elm/default.nix
index 6949f6e3b2a..9dbde319f0a 100644
--- a/pkgs/development/compilers/elm/default.nix
+++ b/pkgs/development/compilers/elm/default.nix
@@ -4,7 +4,7 @@
 let
   fetchElmDeps = import ./fetchElmDeps.nix { inherit stdenv lib fetchurl; };
 
-  hsPkgs = haskell.packages.ghc865.override {
+  hsPkgs = haskell.packages.ghc881.override {
     overrides = self: super: with haskell.lib;
       let elmPkgs = rec {
             elm = overrideCabal (self.callPackage ./packages/elm.nix { }) (drv: {
@@ -12,14 +12,9 @@ let
               enableParallelBuilding = false;
               preConfigure = self.fetchElmDeps {
                 elmPackages = (import ./packages/elm-srcs.nix);
-                versionsDat = ./versions.dat;
+                elmVersion = drv.version;
+                registryDat = ./registry.dat;
               };
-              patches = [
-                (fetchpatch {
-                  url = "https://github.com/elm/compiler/pull/1886/commits/39d86a735e28da514be185d4c3256142c37c2a8a.patch";
-                  sha256 = "0nni5qx1523rjz1ja42z6z9pijxvi3fgbw1dhq5qi11mh1nb9ay7";
-                })
-              ];
               buildTools = drv.buildTools or [] ++ [ makeWrapper ];
               jailbreak = true;
               postInstall = ''
@@ -32,8 +27,14 @@ let
             The elm-format expression is updated via a script in the https://github.com/avh4/elm-format repo:
             `package/nix/build.sh`
             */
-            elm-format = justStaticExecutables (doJailbreak (self.callPackage ./packages/elm-format.nix {}));
-            elmi-to-json = justStaticExecutables (self.callPackage ./packages/elmi-to-json.nix {});
+            #elm-format = justStaticExecutables (doJailbreak (self.callPackage ./packages/elm-format.nix {}));
+            elmi-to-json = justStaticExecutables (overrideCabal (self.callPackage ./packages/elmi-to-json.nix {}) (drv: {
+              prePatch = '' 
+                substituteInPlace package.yaml --replace "- -Werror" ""
+                hpack
+              '';
+              jailbreak = true;
+            }));
 
             inherit fetchElmDeps;
             elmVersion = elmPkgs.elm.version;
diff --git a/pkgs/development/compilers/elm/fetchElmDeps.nix b/pkgs/development/compilers/elm/fetchElmDeps.nix
index 3da2445e0c5..05dffaa9e2e 100644
--- a/pkgs/development/compilers/elm/fetchElmDeps.nix
+++ b/pkgs/development/compilers/elm/fetchElmDeps.nix
@@ -1,11 +1,11 @@
 {stdenv, lib, fetchurl}:
 
-{elmPackages, versionsDat}:
+{elmPackages, registryDat, elmVersion}:
 
 let
-  makeDotElm = import ./makeDotElm.nix {inherit stdenv lib fetchurl versionsDat;};
+  makeDotElm = import ./makeDotElm.nix {inherit stdenv lib fetchurl registryDat;};
 
 in
 ''
   export ELM_HOME=`pwd`/.elm
-'' + (makeDotElm "0.19.0" elmPackages)
+'' + (makeDotElm elmVersion elmPackages)
diff --git a/pkgs/development/compilers/elm/makeDotElm.nix b/pkgs/development/compilers/elm/makeDotElm.nix
index 1bc8e61d27c..3ceaae450f0 100644
--- a/pkgs/development/compilers/elm/makeDotElm.nix
+++ b/pkgs/development/compilers/elm/makeDotElm.nix
@@ -1,4 +1,4 @@
-{stdenv, lib, fetchurl, versionsDat}:
+{stdenv, lib, fetchurl, registryDat}:
 
 ver: deps:
   let cmds = lib.mapAttrsToList (name: info: let
@@ -20,11 +20,11 @@ ver: deps:
 
                };
              in ''
-               mkdir -p .elm/${ver}/package/${name}
-               cp -R ${pkg} .elm/${ver}/package/${name}/${info.version}
+               mkdir -p .elm/${ver}/packages/${name}
+               cp -R ${pkg} .elm/${ver}/packages/${name}/${info.version}
              '') deps;
   in (lib.concatStrings cmds) + ''
-    mkdir -p .elm/${ver}/package;
-    cp ${versionsDat} .elm/${ver}/package/versions.dat;
+    mkdir -p .elm/${ver}/packages;
+    cp ${registryDat} .elm/${ver}/packages/registry.dat;
     chmod -R +w .elm
   ''
diff --git a/pkgs/development/compilers/elm/packages/elm-srcs.nix b/pkgs/development/compilers/elm/packages/elm-srcs.nix
index e1f941626dd..0d4523b8b09 100644
--- a/pkgs/development/compilers/elm/packages/elm-srcs.nix
+++ b/pkgs/development/compilers/elm/packages/elm-srcs.nix
@@ -6,8 +6,8 @@
       };
 
       "elm/json" = {
-        sha256 = "1g0hafkqf2q633r7ir9wxpb1lnlzskhpsyi0h5bkzj0gl072zfnb";
-        version = "1.0.0";
+        sha256 = "1a107nmm905dih4w4mjjkkpdcjbgaf5qjvr7fl30kkpkckfjjnrw";
+        version = "1.1.2";
       };
 
       "elm/html" = {
@@ -16,8 +16,8 @@
       };
 
       "elm/svg" = {
-        sha256 = "08x0v8p9wm699jjmsnbq69pxv3jh60j4f6fg7y6hyr7xxj85y390";
-        version = "1.0.0";
+        sha256 = "1cwcj73p61q45wqwgqvrvz3aypjyy3fw732xyxdyj6s256hwkn0k";
+        version = "1.0.1";
       };
 
       "elm/project-metadata-utils" = {
@@ -26,23 +26,33 @@
       };
 
       "elm/browser" = {
-        sha256 = "1apmvyax93nvmagwj00y16zx10kfv640cxpi64xgqbgy7d2wphy4";
-        version = "1.0.0";
+        sha256 = "1zlmx672glg7fdgkvh5jm47y85pv7pdfr5mkhg6x7ar6k000vyka";
+        version = "1.0.1";
       };
 
       "elm/core" = {
-        sha256 = "10kr86h4v5h4p0586q406a5wbl8xvr1jyrf6097zp2wb8sv21ylw";
-        version = "1.0.0";
+        sha256 = "1l0qdbczw91kzz8sx5d5zwz9x662bspy7p21dsr3f2rigxiix2as";
+        version = "1.0.2";
       };
 
       "elm/http" = {
-        sha256 = "1igmm89ialzrjib1j8xagkxalq1x2gj4l0hfxcd66mpwmvg7psl8";
-        version = "1.0.0";
+        sha256 = "008bs76mnp48b4dw8qwjj4fyvzbxvlrl4xpa2qh1gg2kfwyw56v1";
+        version = "2.0.0";
+      };
+
+      "elm/bytes" = {
+        sha256 = "040d7irrawcbnq9jxhzx8p9qacdlw5bncy6lgndd6inm53rvvwbp";
+        version = "1.0.7";
+      };
+
+      "elm/file" = {
+        sha256 = "15vw1ilbg0msimq2k9magwigp8lwqrgvz3vk6qia6b3ldahvw8jr";
+        version = "1.0.1";
       };
 
       "elm/parser" = {
-        sha256 = "0k4zlq30lrvawqvzwbvsl0hrmwf9s832mb41z7fdspm4549dj7wc";
-        version = "1.0.0";
+        sha256 = "0a3cxrvbm7mwg9ykynhp7vjid58zsw03r63qxipxp3z09qks7512";
+        version = "1.1.0";
       };
 
       "elm/url" = {
@@ -56,7 +66,7 @@
       };
 
       "elm/virtual-dom" = {
-        sha256 = "0hm8g92h7z39km325dlnhk8n00nlyjkqp3r3jppr37k2k13md6aq";
-        version = "1.0.0";
+        sha256 = "0q1v5gi4g336bzz1lgwpn5b1639lrn63d8y6k6pimcyismp2i1yg";
+        version = "1.0.2";
       };
 }
diff --git a/pkgs/development/compilers/elm/packages/elm.nix b/pkgs/development/compilers/elm/packages/elm.nix
index 4edd9bebbc6..644a53fd619 100644
--- a/pkgs/development/compilers/elm/packages/elm.nix
+++ b/pkgs/development/compilers/elm/packages/elm.nix
@@ -1,29 +1,29 @@
 { mkDerivation, ansi-terminal, ansi-wl-pprint, base, binary
 , bytestring, containers, directory, edit-distance, fetchgit
-, file-embed, filepath, ghc-prim, haskeline, HTTP, http-client
-, http-client-tls, http-types, language-glsl, logict, mtl, network
-, parsec, process, raw-strings-qq, scientific, SHA, snap-core
-, snap-server, stdenv, template-haskell, text, time
+, file-embed, filelock, filepath, ghc-prim, haskeline, HTTP
+, http-client, http-client-tls, http-types, language-glsl, mtl
+, network, parsec, process, raw-strings-qq, scientific, SHA
+, snap-core, snap-server, stdenv, template-haskell, time
 , unordered-containers, utf8-string, vector, zip-archive
 }:
 mkDerivation {
   pname = "elm";
-  version = "0.19.0";
+  version = "0.19.1";
   src = fetchgit {
     url = "https://github.com/elm/compiler";
-    sha256 = "13jks6c6i80z71mjjfg46ri570g5ini0k3xw3857v6z66zcl56x4";
-    rev = "d5cbc41aac23da463236bbc250933d037da4055a";
+    sha256 = "1rdg3xp3js9xadclk3cdypkscm5wahgsfmm4ldcw3xswzhw6ri8w";
+    rev = "c9aefb6230f5e0bda03205ab0499f6e4af924495";
     fetchSubmodules = true;
   };
   isLibrary = false;
   isExecutable = true;
   executableHaskellDepends = [
     ansi-terminal ansi-wl-pprint base binary bytestring containers
-    directory edit-distance file-embed filepath ghc-prim haskeline HTTP
-    http-client http-client-tls http-types language-glsl logict mtl
-    network parsec process raw-strings-qq scientific SHA snap-core
-    snap-server template-haskell text time unordered-containers
-    utf8-string vector zip-archive
+    directory edit-distance file-embed filelock filepath ghc-prim
+    haskeline HTTP http-client http-client-tls http-types language-glsl
+    mtl network parsec process raw-strings-qq scientific SHA snap-core
+    snap-server template-haskell time unordered-containers utf8-string
+    vector zip-archive
   ];
   homepage = "https://elm-lang.org";
   description = "The `elm` command line interface";
diff --git a/pkgs/development/compilers/elm/packages/elmi-to-json.nix b/pkgs/development/compilers/elm/packages/elmi-to-json.nix
index f6a0b9e2426..87b02f013f8 100644
--- a/pkgs/development/compilers/elm/packages/elmi-to-json.nix
+++ b/pkgs/development/compilers/elm/packages/elmi-to-json.nix
@@ -1,27 +1,27 @@
-{ mkDerivation, aeson, async, base, binary, bytestring, containers
-, directory, filepath, hpack, optparse-applicative, safe-exceptions
-, stdenv, text, fetchgit
+{ mkDerivation, aeson, base, binary, bytestring, containers
+, directory, fetchgit, filepath, ghc-prim, hpack
+, optparse-applicative, stdenv, text, unliftio
+, unordered-containers
 }:
 mkDerivation {
   pname = "elmi-to-json";
-  version = "0.19.4";
+  version = "1.2.0";
   src = fetchgit {
     url = "https://github.com/stoeffel/elmi-to-json.git";
-    rev = "357ad96f05e4c68023b036f27f6f65c4377c7427";
-    sha256 = "0vj9fdqgg2zd1nxpll6v02fk6bcyhx00xhp3s8sd7ycvirwsim9n";
+    sha256 = "1kxai87h2g0749yq0fkxwk3xaavydraaivhnavbwr62q2hw4wrj7";
+    rev = "af08ceafe742a252f1f1f3c229b0ce3b3e00084d";
+    fetchSubmodules = true;
   };
   isLibrary = true;
   isExecutable = true;
   libraryHaskellDepends = [
-    aeson async base binary bytestring containers directory filepath
-    optparse-applicative safe-exceptions text
+    aeson base binary bytestring containers directory filepath ghc-prim
+    optparse-applicative text unliftio unordered-containers
   ];
   libraryToolDepends = [ hpack ];
   executableHaskellDepends = [ base ];
   testHaskellDepends = [ base ];
-  preConfigure = "hpack";
+  prePatch = "hpack";
   homepage = "https://github.com/stoeffel/elmi-to-json#readme";
-  description = "Translates elmi binary files to JSON representation";
   license = stdenv.lib.licenses.bsd3;
-  maintainers = with stdenv.lib.maintainers; [ turbomack ];
 }
diff --git a/pkgs/development/compilers/elm/registry.dat b/pkgs/development/compilers/elm/registry.dat
new file mode 100644
index 00000000000..14fcb12a746
Binary files /dev/null and b/pkgs/development/compilers/elm/registry.dat differ
diff --git a/pkgs/development/compilers/elm/update.sh b/pkgs/development/compilers/elm/update.sh
index 920b95e5ad9..c2500b462ad 100755
--- a/pkgs/development/compilers/elm/update.sh
+++ b/pkgs/development/compilers/elm/update.sh
@@ -1,8 +1,9 @@
 #!/usr/bin/env nix-shell
 #!nix-shell -p cabal2nix elm2nix -i bash ../../..
 
-cabal2nix https://github.com/elm/compiler --revision d5cbc41aac23da463236bbc250933d037da4055a > packages/elm.nix
-elm2nix snapshot > versions.dat
-pushd "$(nix-build -A elmPackages.elm.src --no-out-link ../../../..)/ui/browser"
+cabal2nix https://github.com/elm/compiler --revision c9aefb6230f5e0bda03205ab0499f6e4af924495 > packages/elm.nix
+echo "need to manually copy registry.dat from an existing elm project"
+#elm2nix snapshot > registry.dat
+pushd "$(nix-build -A elmPackages.elm.src --no-out-link ../../../..)/reactor"
   elm2nix convert > $OLDPWD/packages/elm-srcs.nix
 popd
diff --git a/pkgs/development/compilers/elm/versions.dat b/pkgs/development/compilers/elm/versions.dat
deleted file mode 100644
index 9dcfd8a2808..00000000000
Binary files a/pkgs/development/compilers/elm/versions.dat and /dev/null differ
diff --git a/pkgs/development/haskell-modules/configuration-ghc-8.8.x.nix b/pkgs/development/haskell-modules/configuration-ghc-8.8.x.nix
index 79210747260..5c54a90ce7e 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-8.8.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-8.8.x.nix
@@ -66,6 +66,7 @@ self: super: {
   th-expand-syns = doJailbreak super.th-expand-syns;
   # TODO: remove when upstream accepts https://github.com/snapframework/io-streams-haproxy/pull/17
   io-streams-haproxy = doJailbreak super.io-streams-haproxy; # base >=4.5 && <4.13
+  snap-server = doJailbreak super.snap-server;
 
   # use latest version to fix the build
   generics-sop = self.generics-sop_0_5_0_0;
@@ -106,6 +107,15 @@ self: super: {
     url = "https://github.com/simonmar/alex/commit/deaae6eddef5186bfd0e42e2c3ced39e26afa4d6.patch";
     sha256 = "1v40gmnw4lqyk271wngdwz8whpfdhmza58srbkka8icwwwrck3l5";
   });
+  # https://github.com/snapframework/snap-core/issues/288
+  snap-core = overrideCabal super.snap-core (drv: { prePatch = "substituteInPlace src/Snap/Internal/Core.hs --replace 'fail   = Fail.fail' ''"; });
+  # needs a release
+  json = overrideCabal super.json (drv: { prePatch = "substituteInPlace json.cabal --replace '4.13' '4.14'"; patches = [(
+    pkgs.fetchpatch {
+      url = "https://github.com/GaloisInc/json/commit/9d36ca5d865be7e4b2126b68a444b901941d2492.patch";
+      sha256 = "0vyi5nbivkqg6zngq7rb3wwcj9043m4hmyk155nrcddl8j2smfzv";
+    }
+  )]; });
 
   # Upstream ships a broken Setup.hs file.
   csv = overrideCabal super.csv (drv: { prePatch = "rm Setup.hs"; });