diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index 40bd4a7f0c9ac..e4dac4a886129 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -953,13 +953,6 @@ self: super: {
   # https://github.com/yesodweb/Shelly.hs/issues/162
   shelly = dontCheck super.shelly;
 
-  # https://github.com/simonmichael/hledger/issues/852
-  hledger-lib = appendPatch super.hledger-lib (pkgs.fetchpatch {
-    url = "https://github.com/simonmichael/hledger/commit/007b9f8caaf699852511634752a7d7c86f6adc67.patch";
-    sha256 = "1lfp29mi1qyrcr9nfjigbyric0xb9n4ann5w6sr0g5sanr4maqs2";
-    stripLen = 1;
-  });
-
   # Copy hledger man pages from data directory into the proper place. This code
   # should be moved into the cabal2nix generator.
   hledger = overrideCabal super.hledger (drv: {
diff --git a/pkgs/development/haskell-modules/configuration-hackage2nix.yaml b/pkgs/development/haskell-modules/configuration-hackage2nix.yaml
index cdc6a25f016ab..aee9b8df8fa3f 100644
--- a/pkgs/development/haskell-modules/configuration-hackage2nix.yaml
+++ b/pkgs/development/haskell-modules/configuration-hackage2nix.yaml
@@ -43,6 +43,8 @@ core-packages:
 default-package-overrides:
   # Newer versions require contravariant-1.5.*, which many builds refuse at the moment.
   - base-compat-batteries ==0.10.1
+  # Newer versions don't work in LTS-12.x
+  - cassava-megaparsec < 2
   # LTS Haskell 12.11
   - abstract-deque ==0.3
   - abstract-deque-tests ==0.3