diff --git a/pkgs/development/ocaml-modules/pgsolver/default.nix b/pkgs/development/ocaml-modules/pgsolver/default.nix
index 5a6392ca70fc..a9880ce370ed 100644
--- a/pkgs/development/ocaml-modules/pgsolver/default.nix
+++ b/pkgs/development/ocaml-modules/pgsolver/default.nix
@@ -4,7 +4,8 @@
   fetchpatch,
   buildOasisPackage,
   ounit,
-  tcslib,
+  tcs-lib,
+  extlib,
   ocaml-sat-solvers,
 }:
 
@@ -29,9 +30,15 @@ buildOasisPackage rec {
     ];
   };
 
+  # Compatibility with tcs-lib ≥ 0.6
+  postPatch = ''
+    substituteInPlace _oasis --replace-fail TCSLib tcs-lib
+  '';
+
   buildInputs = [ ounit ];
   propagatedBuildInputs = [
-    tcslib
+    extlib
+    tcs-lib
     ocaml-sat-solvers
   ];
 
diff --git a/pkgs/development/ocaml-modules/tcs-lib/default.nix b/pkgs/development/ocaml-modules/tcs-lib/default.nix
new file mode 100644
index 000000000000..55443ab7969b
--- /dev/null
+++ b/pkgs/development/ocaml-modules/tcs-lib/default.nix
@@ -0,0 +1,29 @@
+{
+  lib,
+  fetchurl,
+  buildDunePackage,
+  num,
+}:
+
+buildDunePackage (finalAttrs: {
+  pname = "tcs-lib";
+  version = "0.6";
+
+  minimalOCamlVersion = "4.03";
+
+  src = fetchurl {
+    url = "https://github.com/tcsprojects/tcslib/releases/download/v${finalAttrs.version}/tcs-lib-${finalAttrs.version}.tbz";
+    hash = "sha256-DBjdIOUrYbfN3VlTaQMIGezPpOpzv9vtmDmBVYZigSI=";
+  };
+
+  propagatedBuildInputs = [
+    num
+  ];
+
+  meta = {
+    homepage = "https://github.com/tcsprojects/tcslib";
+    description = "Multi-purpose library for OCaml";
+    license = lib.licenses.bsd3;
+    maintainers = with lib.maintainers; [ mgttlinger ];
+  };
+})
diff --git a/pkgs/development/ocaml-modules/tcslib/default.nix b/pkgs/development/ocaml-modules/tcslib/default.nix
deleted file mode 100644
index 58c19e399cc4..000000000000
--- a/pkgs/development/ocaml-modules/tcslib/default.nix
+++ /dev/null
@@ -1,33 +0,0 @@
-{
-  lib,
-  fetchFromGitHub,
-  buildOasisPackage,
-  extlib,
-  num,
-}:
-
-buildOasisPackage rec {
-  pname = "tcslib";
-  version = "0.3";
-
-  minimumOCamlVersion = "4.03.0";
-
-  src = fetchFromGitHub {
-    owner = "tcsprojects";
-    repo = "tcslib";
-    rev = "v${version}";
-    sha256 = "05g6m82blsccq8wx8knxv6a5fzww7hi624jx91f9h87nk2fsplhi";
-  };
-
-  propagatedBuildInputs = [
-    extlib
-    num
-  ];
-
-  meta = {
-    homepage = "https://github.com/tcsprojects/tcslib";
-    description = "Multi-purpose library for OCaml";
-    license = lib.licenses.bsd3;
-    maintainers = with lib.maintainers; [ mgttlinger ];
-  };
-}
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index f884a3d7ad7f..5bfb4349e55a 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -2001,7 +2001,7 @@ let
 
         tcpip = callPackage ../development/ocaml-modules/tcpip { };
 
-        tcslib = callPackage ../development/ocaml-modules/tcslib { };
+        tcs-lib = callPackage ../development/ocaml-modules/tcs-lib { };
 
         tdigest = callPackage ../development/ocaml-modules/tdigest { };