diff --git a/pkgs/by-name/op/open-web-calendar/package.nix b/pkgs/by-name/op/open-web-calendar/package.nix
index 5e77b50f470b..0d8c0cc7cac9 100644
--- a/pkgs/by-name/op/open-web-calendar/package.nix
+++ b/pkgs/by-name/op/open-web-calendar/package.nix
@@ -12,7 +12,7 @@ let
 in
 python.pkgs.buildPythonApplication rec {
   pname = "open-web-calendar";
-  version = "1.42";
+  version = "1.48";
   pyproject = true;
 
   disabled = python.pythonOlder "3.9";
@@ -20,7 +20,7 @@ python.pkgs.buildPythonApplication rec {
   src = fetchPypi {
     inherit version;
     pname = "open_web_calendar";
-    hash = "sha256-w4XaT1+qIM80K6B+LIAeYdZzYIw4FYSd/nvWphOx460=";
+    hash = "sha256-SSe5vkrfTpUFdSLglBxo5//VZfuXYnWs5sUKJL2zWOw=";
   };
 
   # The Pypi tarball doesn't contain open_web_calendars/features
@@ -35,6 +35,7 @@ python.pkgs.buildPythonApplication rec {
   build-system = with python.pkgs; [
     hatchling
     hatch-vcs
+    hatch-requirements-txt
   ];
 
   dependencies =
@@ -44,6 +45,10 @@ python.pkgs.buildPythonApplication rec {
       flask-allowed-hosts
       flask
       icalendar
+      icalendar-compatibility
+      cryptography
+      bcrypt
+      caldav
       requests
       pyyaml
       recurring-ical-events
@@ -52,6 +57,7 @@ python.pkgs.buildPythonApplication rec {
       beautifulsoup4
       lxml-html-clean
       pytz
+      mergecal
     ]
     ++ requests.optional-dependencies.socks;
 
diff --git a/pkgs/development/python-modules/icalendar-compatibility/default.nix b/pkgs/development/python-modules/icalendar-compatibility/default.nix
new file mode 100644
index 000000000000..b5969bcca32b
--- /dev/null
+++ b/pkgs/development/python-modules/icalendar-compatibility/default.nix
@@ -0,0 +1,53 @@
+{
+  lib,
+  buildPythonPackage,
+  fetchFromGitHub,
+  hatchling,
+  hatch-vcs,
+  icalendar,
+  pytestCheckHook,
+  git,
+}:
+
+buildPythonPackage rec {
+  pname = "icalendar-compatibility";
+  version = "0.1.4";
+  pyproject = true;
+
+  src = fetchFromGitHub {
+    owner = "niccokunzmann";
+    repo = "icalendar_compatibility";
+    tag = "v${version}";
+    hash = "sha256-h9rpbltNEPMteicPJ6oC32NsZS8QXQphLbC0Qiu7j5Q=";
+  };
+
+  # hatch-vcs tries to read the current git commit hash
+  postPatch = ''
+    substituteInPlace pyproject.toml \
+      --replace 'dynamic = ["urls", "version"]' 'version = "${version}"'
+  '';
+
+  build-system = [
+    hatchling
+    hatch-vcs
+  ];
+
+  dependencies = [ icalendar ];
+
+  nativeCheckInputs = [
+    pytestCheckHook
+    git
+  ];
+
+  pythonImportsCheck = [ "icalendar_compatibility" ];
+
+  # env.SETUPTOOLS_SCM_PRETEND_VERSION = version;
+
+  meta = {
+    homepage = "https://icalendar-compatibility.readthedocs.io/en/latest/";
+    changelog = "https://icalendar-compatibility.readthedocs.io/en/latest/changes.html";
+    license = lib.licenses.gpl2Plus;
+    maintainers = with lib.maintainers; [ erictapen ];
+  };
+
+}
diff --git a/pkgs/development/python-modules/mergecal/default.nix b/pkgs/development/python-modules/mergecal/default.nix
new file mode 100644
index 000000000000..25d038f02b36
--- /dev/null
+++ b/pkgs/development/python-modules/mergecal/default.nix
@@ -0,0 +1,48 @@
+{
+  lib,
+  buildPythonPackage,
+  fetchFromGitHub,
+  setuptools,
+  icalendar,
+  rich,
+  typer,
+  x-wr-timezone,
+  pytestCheckHook,
+  pytest-cov-stub,
+}:
+
+buildPythonPackage rec {
+  pname = "mergecal";
+  version = "0.5.0";
+  pyproject = true;
+
+  src = fetchFromGitHub {
+    owner = "mergecal";
+    repo = "python-mergecal";
+    tag = "v${version}";
+    hash = "sha256-Je3gFREu97Ycofszhr6pKOCiK76oBuzb3ji4LAf5aE8=";
+  };
+
+  build-system = [ setuptools ];
+
+  dependencies = [
+    icalendar
+    rich
+    typer
+    x-wr-timezone
+  ];
+
+  nativeCheckInputs = [
+    pytestCheckHook
+    pytest-cov-stub
+  ];
+
+  pythonImportChecks = [ "mergecal" ];
+
+  meta = {
+    homepage = "https://mergecal.readthedocs.io/en/latest/";
+    changelog = "https://github.com/mergecal/python-mergecal/blob/${src.tag}/CHANGELOG.md";
+    license = lib.licenses.gpl3Only;
+    maintainers = with lib.maintainers; [ erictapen ];
+  };
+}
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 5264737ca668..9540defc0874 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -6322,6 +6322,8 @@ self: super: with self; {
 
   icalendar = callPackage ../development/python-modules/icalendar { };
 
+  icalendar-compatibility = callPackage ../development/python-modules/icalendar-compatibility { };
+
   icalevents = callPackage ../development/python-modules/icalevents { };
 
   icecream = callPackage ../development/python-modules/icecream { };
@@ -8307,6 +8309,8 @@ self: super: with self; {
 
   merge3 = callPackage ../development/python-modules/merge3 { };
 
+  mergecal = callPackage ../development/python-modules/mergecal { };
+
   mergedb = callPackage ../development/python-modules/mergedb { };
 
   mergedeep = callPackage ../development/python-modules/mergedeep { };