diff --git a/pkgs/development/python-modules/pyyaml-env-tag/default.nix b/pkgs/development/python-modules/pyyaml-env-tag/default.nix
new file mode 100644
index 000000000000..f81bbbd7acbf
--- /dev/null
+++ b/pkgs/development/python-modules/pyyaml-env-tag/default.nix
@@ -0,0 +1,36 @@
+{ lib
+, buildPythonPackage
+, fetchPypi
+, pythonOlder
+, pyyaml
+, pytestCheckHook
+}:
+
+buildPythonPackage rec {
+  pname = "pyyaml-env-tag";
+  version = "0.1";
+  disabled = pythonOlder "3.6";
+
+  src = fetchPypi {
+    pname = "pyyaml_env_tag";
+    inherit version;
+    sha256 = "1nsva88jsmwn0cb9jnrfiz4dvs9xakkpgfii7g1xwkx1pmsjc2bh";
+  };
+
+  propagatedBuildInputs = [
+    pyyaml
+  ];
+
+  checkInputs = [
+    pytestCheckHook
+  ];
+
+  pythonImportsCheck = [ "yaml_env_tag" ];
+
+  meta = with lib; {
+    description = "Custom YAML tag for referencing environment variables";
+    homepage = "https://github.com/waylan/pyyaml-env-tag";
+    license = with licenses; [ mit ];
+    maintainers = with maintainers; [ fab ];
+  };
+}
diff --git a/pkgs/development/tools/documentation/mkdocs/default.nix b/pkgs/development/tools/documentation/mkdocs/default.nix
index 64d834f1bb29..f7774cc7127e 100644
--- a/pkgs/development/tools/documentation/mkdocs/default.nix
+++ b/pkgs/development/tools/documentation/mkdocs/default.nix
@@ -1,40 +1,55 @@
-{ lib, python3, fetchFromGitHub }:
+{ lib
+, python3
+, fetchFromGitHub
+}:
 
 with python3.pkgs;
 
 buildPythonApplication rec {
   pname = "mkdocs";
-  version = "1.0.4";
+  version = "1.2.1";
+  disabled = pythonOlder "3.6";
 
   src = fetchFromGitHub {
-    owner = "mkdocs";
-    repo = "mkdocs";
+    owner = pname;
+    repo = pname;
     rev = version;
-    sha256 = "1x35vgiskgz4wwrvi4m1mri5wlphf15p90fr3rxsy5bf19v3s9hs";
+    sha256 = "sha256-JF3Zz1ObxeKsIF0pa8duJxqjLgMvmWsWMApHT43Z+EY=";
   };
 
-  checkInputs = [
-    nose nose-exclude mock
-  ];
-
-  NOSE_EXCLUDE_TESTS = lib.concatStringsSep ";" [
-    "mkdocs.tests.gh_deploy_tests.TestGitHubDeploy"
-    "mkdocs.tests.config.config_tests.ConfigTests"
-    "mkdocs.tests.config.config_options_tests.DirTest"
-  ];
-
-  checkPhase = "nosetests mkdocs";
-
   propagatedBuildInputs = [
-    tornado
-    livereload
     click
-    pyyaml
-    markdown
     jinja2
-    backports_tempfile
+    markdown
+    mergedeep
+    pyyaml
+    pyyaml-env-tag
+    ghp-import
+    importlib-metadata
+    watchdog
+    packaging
   ];
 
+  checkInputs = [
+    Babel
+    mock
+    pytestCheckHook
+  ];
+
+  postPatch = ''
+    # Remove test due to missing requirement
+    rm mkdocs/tests/theme_tests.py
+  '';
+
+  pytestFlagsArray = [ "mkdocs/tests/*.py" ];
+
+  disabledTests = [
+    # Don't start a test server
+    "testing_server"
+  ];
+
+  pythonImportsCheck = [ "mkdocs" ];
+
   meta = with lib; {
     description = "Project documentation with Markdown / static website generator";
     longDescription = ''
@@ -42,11 +57,11 @@ buildPythonApplication rec {
       geared towards building project documentation. Documentation source files
       are written in Markdown, and configured with a single YAML configuration file.
 
-      MkDocs can also be used to generate general-purpose Websites.
+      MkDocs can also be used to generate general-purpose websites.
     '';
     homepage = "http://mkdocs.org/";
-    license = lib.licenses.bsd2;
+    license = licenses.bsd2;
     platforms = platforms.unix;
-    maintainers = [ maintainers.rkoe ];
+    maintainers = with maintainers; [ rkoe ];
   };
 }
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 41570dce0094..9d5f97f6def8 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -7184,6 +7184,8 @@ in {
 
   pyyaml = callPackage ../development/python-modules/pyyaml { };
 
+  pyyaml-env-tag = callPackage ../development/python-modules/pyyaml-env-tag { };
+
   pyzerproc = callPackage ../development/python-modules/pyzerproc { };
 
   pyzmq = callPackage ../development/python-modules/pyzmq { };