diff --git a/pkgs/development/haskell-modules/configuration-ghc-9.12.x.nix b/pkgs/development/haskell-modules/configuration-ghc-9.12.x.nix
index 0b91bb367f0d..bcc254bda498 100644
--- a/pkgs/development/haskell-modules/configuration-ghc-9.12.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghc-9.12.x.nix
@@ -1,12 +1,29 @@
 { pkgs, haskellLib }:
 
+self: super:
+
 let
   inherit (pkgs) lib;
+
+  versionAtMost = a: b: lib.versionAtLeast b a;
+
+  warnVersion =
+    predicate: ver: pkg:
+    let
+      pname = pkg.pname;
+    in
+    lib.warnIf (predicate ver
+      super.${pname}.version
+    ) "override for haskell.packages.ghc912.${pname} may no longer be needed" pkg;
+
+  warnAfterVersion = warnVersion lib.versionOlder;
+  warnFromVersion = warnVersion versionAtMost;
+
 in
 
 with haskellLib;
 
-self: super: {
+{
   llvmPackages = lib.dontRecurseIntoAttrs self.ghc.llvmPackages;
 
   # Disable GHC core libraries
@@ -58,6 +75,12 @@ self: super: {
   xhtml = null;
 
   doctest = self.doctest_0_23_0;
+
+  constraints-extras = warnFromVersion "0.4.0.2" (doDistribute self.constraints-extras_0_4_0_2);
+  dependent-sum-template = warnFromVersion "0.2.0.2" (
+    doDistribute self.dependent-sum-template_0_2_0_2
+  );
+  haskell-src-meta = warnFromVersion "0.8.15" (doDistribute self.haskell-src-meta_0_8_15);
   htree = doDistribute self.htree_0_2_0_0;
   tagged = doDistribute self.tagged_0_8_9;
   time-compat = doDistribute (doJailbreak self.time-compat_1_9_8); # too strict lower bound on QuickCheck
@@ -83,4 +106,7 @@ self: super: {
         export alex_datadir="$(pwd)/data"
       '';
   }) super.alex;
+
+  # https://github.com/sjakobi/newtype-generics/pull/28/files
+  newtype-generics = warnAfterVersion "0.6.2" (doJailbreak super.newtype-generics);
 }
diff --git a/pkgs/development/haskell-modules/configuration-ghcjs-9.x.nix b/pkgs/development/haskell-modules/configuration-ghcjs-9.x.nix
index f4f88d4a4e51..b9d5a072a95d 100644
--- a/pkgs/development/haskell-modules/configuration-ghcjs-9.x.nix
+++ b/pkgs/development/haskell-modules/configuration-ghcjs-9.x.nix
@@ -1,5 +1,9 @@
 { pkgs, haskellLib }:
 
+let
+  inherit (pkgs) lib;
+in
+
 with haskellLib;
 
 # cabal2nix doesn't properly add dependencies conditional on arch(javascript)
@@ -27,7 +31,10 @@ with haskellLib;
   patch = haskellLib.disableParallelBuilding super.patch;
   reflex-dom-core = haskellLib.disableParallelBuilding super.reflex-dom-core;
 
-  reflex-dom = super.reflex-dom.override (drv: {
-    jsaddle-webkit2gtk = null;
-  });
+  reflex-dom =
+    lib.warn "reflex-dom builds with JS backend but it is missing fixes for working at runtime"
+      super.reflex-dom.override
+      (drv: {
+        jsaddle-webkit2gtk = null;
+      });
 })
diff --git a/pkgs/top-level/release-haskell.nix b/pkgs/top-level/release-haskell.nix
index 2e59d6483bff..f05ba18240e9 100644
--- a/pkgs/top-level/release-haskell.nix
+++ b/pkgs/top-level/release-haskell.nix
@@ -506,6 +506,16 @@ let
                   ;
               };
 
+              haskell.packages.ghc912 = {
+                inherit (packagePlatforms pkgs.pkgsCross.ghcjs.haskell.packages.ghc912)
+                  ghc
+                  hello
+                  microlens
+                  miso
+                  reflex-dom
+                  ;
+              };
+
               haskell.packages.ghcHEAD = {
                 inherit (packagePlatforms pkgs.pkgsCross.ghcjs.haskell.packages.ghcHEAD)
                   ghc