diff --git a/pkgs/development/python-modules/flask-marshmallow/default.nix b/pkgs/development/python-modules/flask-marshmallow/default.nix
index be74af2d5f9a..fdc40c244303 100644
--- a/pkgs/development/python-modules/flask-marshmallow/default.nix
+++ b/pkgs/development/python-modules/flask-marshmallow/default.nix
@@ -1,13 +1,13 @@
 { lib
 , buildPythonPackage
 , fetchFromGitHub
-, pythonOlder
-, flit-core
 , flask
-, marshmallow
-, pytestCheckHook
 , flask-sqlalchemy
+, flit-core
+, marshmallow
 , marshmallow-sqlalchemy
+, pytestCheckHook
+, pythonOlder
 }:
 
 buildPythonPackage rec {
@@ -33,6 +33,13 @@ buildPythonPackage rec {
     marshmallow
   ];
 
+  passthru.optional-dependencies = {
+    sqlalchemy = [
+      flask-sqlalchemy
+      marshmallow-sqlalchemy
+    ];
+  };
+
   nativeCheckInputs = [
     pytestCheckHook
   ] ++ passthru.optional-dependencies.sqlalchemy;
@@ -41,12 +48,10 @@ buildPythonPackage rec {
     "flask_marshmallow"
   ];
 
-  passthru.optional-dependencies = {
-    sqlalchemy = [
-      flask-sqlalchemy
-      marshmallow-sqlalchemy
-    ];
-  };
+  pytestFlagsArray = [
+    "-W"
+    "ignore::DeprecationWarning"
+  ];
 
   meta = {
     description = "Flask + marshmallow for beautiful APIs";
diff --git a/pkgs/development/python-modules/marshmallow-oneofschema/default.nix b/pkgs/development/python-modules/marshmallow-oneofschema/default.nix
index 3e4faf8c6031..933f5cc4c8b9 100644
--- a/pkgs/development/python-modules/marshmallow-oneofschema/default.nix
+++ b/pkgs/development/python-modules/marshmallow-oneofschema/default.nix
@@ -4,26 +4,29 @@
 , marshmallow
 , pytestCheckHook
 , pythonOlder
-, setuptools
+, flit-core
 }:
 
 buildPythonPackage rec {
   pname = "marshmallow-oneofschema";
-  version = "3.0.2";
-  format = "setuptools";
+  version = "3.1.1";
+  pyproject = true;
 
-  disabled = pythonOlder "3.6";
+  disabled = pythonOlder "3.8";
 
   src = fetchFromGitHub {
     owner = "marshmallow-code";
-    repo = pname;
-    rev = version;
-    hash = "sha256-Em2jQmvI5IiWREeOX/JAcdOQlpwP7k+cbCirkh82sf0=";
+    repo = "marshmallow-oneofschema";
+    rev = "refs/tags/${version}";
+    hash = "sha256-HXuyUxU8bT5arpUzmgv7m+X2fNT0qHY8S8Rz6klOGiA=";
   };
 
+  nativeBuildInputs = [
+    flit-core
+  ];
+
   propagatedBuildInputs = [
     marshmallow
-    setuptools
   ];
 
   nativeCheckInputs = [
@@ -35,8 +38,8 @@ buildPythonPackage rec {
   ];
 
   meta = with lib; {
-    changelog = "https://github.com/marshmallow-code/marshmallow-oneofschema/blob/${src.rev}/CHANGELOG.rst";
     description = "Marshmallow library extension that allows schema (de)multiplexing";
+    changelog = "https://github.com/marshmallow-code/marshmallow-oneofschema/blob/${version}/CHANGELOG.rst";
     homepage = "https://github.com/marshmallow-code/marshmallow-oneofschema";
     license = licenses.mit;
     maintainers = with maintainers; [ ivan-tkatchev ];
diff --git a/pkgs/development/python-modules/marshmallow/default.nix b/pkgs/development/python-modules/marshmallow/default.nix
index 880e3c869aab..bbb336884c19 100644
--- a/pkgs/development/python-modules/marshmallow/default.nix
+++ b/pkgs/development/python-modules/marshmallow/default.nix
@@ -1,17 +1,17 @@
 { lib
 , buildPythonPackage
 , fetchFromGitHub
+, flit-core
+, packaging
 , pytestCheckHook
 , pythonOlder
 , pytz
 , simplejson
-, packaging
-, setuptools
 }:
 
 buildPythonPackage rec {
   pname = "marshmallow";
-  version = "3.20.2";
+  version = "3.21.1";
   pyproject = true;
 
   disabled = pythonOlder "3.8";
@@ -20,11 +20,11 @@ buildPythonPackage rec {
     owner = "marshmallow-code";
     repo = "marshmallow";
     rev = "refs/tags/${version}";
-    hash = "sha256-z6Quf6uTelGwB/uYayVXtVmculwaoI5LL8I0kKiM/e8=";
+    hash = "sha256-KhXasYKooZRokRoFlWKOaQzSUe6tXDtUlrf65eGGUi8=";
   };
 
   nativeBuildInputs = [
-    setuptools
+    flit-core
   ];
 
   propagatedBuildInputs = [