diff --git a/pkgs/by-name/oa/oama/package.nix b/pkgs/by-name/oa/oama/package.nix
index e938805bac86..1f87b3bffe43 100644
--- a/pkgs/by-name/oa/oama/package.nix
+++ b/pkgs/by-name/oa/oama/package.nix
@@ -15,14 +15,7 @@ let
     passthru.updateScript = ./update.sh;
   };
 
-  raw-pkg = (haskellPackages.callPackage ./generated-package.nix { }).overrideScope (
-    final: prev: {
-      # Dependency twain requires an older version of http2, and we cannot mix
-      # versions of transitive dependencies.
-      http2 = final.http2_3_0_3;
-      warp = final.warp_3_3_30;
-    }
-  );
+  raw-pkg = haskellPackages.callPackage ./generated-package.nix { };
 in
 lib.pipe raw-pkg [
   (overrideCabal overrides)
diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index 2a37000fee8f..f265f86fb963 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -362,15 +362,6 @@ self: super: {
   ]
     super.threadscope);
 
-  # http2 also overridden in all-packages.nix for mailctl.
-  # twain is currently only used by mailctl, so the .overrideScope shouldn't
-  # negatively affect any other packages, at least currently...
-  # https://github.com/alexmingoia/twain/issues/5
-  twain = super.twain.overrideScope (self: _: {
-    http2 = self.http2_3_0_3;
-    warp = self.warp_3_3_30;
-  });
-
   # The latest release on hackage has an upper bound on containers which
   # breaks the build, though it works with the version of containers present
   # and the upper bound doesn't exist in code anymore:
diff --git a/pkgs/development/haskell-modules/configuration-hackage2nix/main.yaml b/pkgs/development/haskell-modules/configuration-hackage2nix/main.yaml
index a53ca9b9162d..279fedc18701 100644
--- a/pkgs/development/haskell-modules/configuration-hackage2nix/main.yaml
+++ b/pkgs/development/haskell-modules/configuration-hackage2nix/main.yaml
@@ -73,7 +73,6 @@ extra-packages:
   - hspec-discover < 2.8                # 2022-04-07: Needed for tasty-hspec 1.1.6
   - hspec-megaparsec == 2.2.0           # 2023-11-18: Latest version compatible with ghc 9.0, needed for HLS
   - hspec-meta < 2.8                    # 2022-12-07: Needed for elmPackages.elm / hspec-discover
-  - http2 < 3.3                         # 2023-08-24: Needed for twain <https://github.com/alexmingoia/twain/issues/5>
   - immortal == 0.2.2.1                 # required by Hasura 1.3.1, 2020-08-20
   - language-docker == 11.0.0           # required by hadolint 2.12.0, 2022-11-16
   - language-javascript == 0.7.0.0      # required by purescript
@@ -90,7 +89,6 @@ extra-packages:
   - primitive-unlifted == 0.1.3.1       # 2024-03-16: Needed for hls on ghc 9.2
   - stylish-haskell == 0.14.4.0         # 2022-09-19: needed for hls on ghc 9.2
   - text == 2.0.2                       # 2023-09-14: Needed for elm (which is currently on ghc-8.10)
-  - warp < 3.3.31                       # 2024-03-20: for twain, which requires http2 3.0.3
   - weeder == 2.2.*                     # 2022-02-21: preserve for GHC 8.10.7
   - weeder == 2.3.*                     # 2022-05-31: preserve for GHC 9.0.2
   - weeder == 2.4.*                     # 2023-02-02: preserve for GHC 9.2.*
diff --git a/pkgs/development/haskell-modules/configuration-nix.nix b/pkgs/development/haskell-modules/configuration-nix.nix
index a41c02d7918a..f6e2ad0755c1 100644
--- a/pkgs/development/haskell-modules/configuration-nix.nix
+++ b/pkgs/development/haskell-modules/configuration-nix.nix
@@ -410,7 +410,6 @@ self: super: builtins.intersectAttrs super {
 
   # The curl executable is required for withApplication tests.
   warp = addTestToolDepend pkgs.curl super.warp;
-  warp_3_3_30 = addTestToolDepend pkgs.curl super.warp_3_3_30;
 
   safe-exceptions = overrideCabal (drv: {
     # Fix strictDeps build error "could not execute: hspec-discover"
diff --git a/pkgs/development/haskell-modules/hackage-packages.nix b/pkgs/development/haskell-modules/hackage-packages.nix
index b0766569d38f..aa47d771c7e3 100644
--- a/pkgs/development/haskell-modules/hackage-packages.nix
+++ b/pkgs/development/haskell-modules/hackage-packages.nix
@@ -167967,41 +167967,6 @@ self: {
        broken = true;
      }) {};
 
-  "http2_3_0_3" = callPackage
-    ({ mkDerivation, aeson, aeson-pretty, array, async, base
-     , base16-bytestring, bytestring, case-insensitive, containers
-     , cryptonite, directory, filepath, gauge, Glob, heaps, hspec
-     , hspec-discover, http-types, mwc-random, network
-     , network-byte-order, network-run, psqueues, stm, text
-     , time-manager, typed-process, unix-time, unordered-containers
-     , vector
-     }:
-     mkDerivation {
-       pname = "http2";
-       version = "3.0.3";
-       sha256 = "1kv99i3pnnx31xndlkaczrpd2j5mvzbqlfz1kaw6cwlwkdnl5bhv";
-       isLibrary = true;
-       isExecutable = true;
-       libraryHaskellDepends = [
-         array async base bytestring case-insensitive containers http-types
-         network network-byte-order psqueues stm time-manager unix-time
-       ];
-       testHaskellDepends = [
-         aeson aeson-pretty async base base16-bytestring bytestring
-         cryptonite directory filepath Glob hspec http-types network
-         network-byte-order network-run text typed-process
-         unordered-containers vector
-       ];
-       testToolDepends = [ hspec-discover ];
-       benchmarkHaskellDepends = [
-         array base bytestring case-insensitive containers gauge heaps
-         mwc-random network-byte-order psqueues stm
-       ];
-       description = "HTTP/2 library";
-       license = lib.licenses.bsd3;
-       hydraPlatforms = lib.platforms.none;
-     }) {};
-
   "http2" = callPackage
     ({ mkDerivation, aeson, aeson-pretty, array, async, base
      , base16-bytestring, bytestring, case-insensitive, containers
@@ -330807,42 +330772,6 @@ self: {
        broken = true;
      }) {};
 
-  "warp_3_3_30" = callPackage
-    ({ mkDerivation, array, auto-update, base, bsb-http-chunked
-     , bytestring, case-insensitive, containers, crypton-x509, directory
-     , gauge, ghc-prim, hashable, hspec, hspec-discover, http-client
-     , http-date, http-types, http2, iproute, network, process
-     , QuickCheck, recv, simple-sendfile, stm, streaming-commons, text
-     , time-manager, unix, unliftio, vault, wai, word8
-     }:
-     mkDerivation {
-       pname = "warp";
-       version = "3.3.30";
-       sha256 = "1i5fnvc9n7w013asj7ckpfb59ybbvhif4d6f4g5jwwad50jmlbpg";
-       libraryHaskellDepends = [
-         array auto-update base bsb-http-chunked bytestring case-insensitive
-         containers crypton-x509 ghc-prim hashable http-date http-types
-         http2 iproute network recv simple-sendfile stm streaming-commons
-         text time-manager unix unliftio vault wai word8
-       ];
-       testHaskellDepends = [
-         array auto-update base bsb-http-chunked bytestring case-insensitive
-         containers crypton-x509 directory ghc-prim hashable hspec
-         http-client http-date http-types http2 iproute network process
-         QuickCheck recv simple-sendfile stm streaming-commons text
-         time-manager unix unliftio vault wai word8
-       ];
-       testToolDepends = [ hspec-discover ];
-       benchmarkHaskellDepends = [
-         auto-update base bytestring containers crypton-x509 gauge hashable
-         http-date http-types network recv time-manager unix unliftio
-       ];
-       description = "A fast, light-weight web server for WAI applications";
-       license = lib.licenses.mit;
-       hydraPlatforms = lib.platforms.none;
-       maintainers = [ lib.maintainers.alexfmpe ];
-     }) {};
-
   "warp" = callPackage
     ({ mkDerivation, array, auto-update, base, bsb-http-chunked
      , bytestring, case-insensitive, containers, crypton-x509, directory