diff --git a/.github/codecov.yml b/.github/codecov.yml
new file mode 100644
index 0000000..f270f3c
--- /dev/null
+++ b/.github/codecov.yml
@@ -0,0 +1,5 @@
+# To validate this file on changes before committing, see https://api.codecov.io/validate
+
+codecov:
+  notify:
+    after_n_builds: 2
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index b241d7d..d91228c 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -5,30 +5,34 @@ on:
     tags:
     - '*'
 
+permissions:
+  contents: read
+
 jobs:
   deploy:
     if: github.repository == 'jazzband/icalevents'
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - name: "Checkout repository with all history for all branches and tags"
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
-      - name: Set up Python
+      - name: "Set up latest Python 3 version"
         uses: actions/setup-python@v5
         with:
-          python-version: '3.x'
+          python-version: "3.x"
 
-      - name: Install dependencies
-        run: |
-          python -m pip install --upgrade pip
-          pip install poetry==2.0.1
+      - name: "Install poetry"
+        uses: abatilo/actions-poetry@v3
+        with:
+          poetry-version: "2.0.1"
 
-      - name: Build package
+      - name: "Build package"
         run: poetry build
 
-      - name: Upload packages to Jazzband
+      - name: "Upload packages to Jazzband"
         if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags')
         uses: pypa/gh-action-pypi-publish@release/v1
         with:
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index c512e49..2db91a5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -1,6 +1,3 @@
-# This workflow will install Python dependencies, run tests and lint with a single version of Python
-# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
-
 name: Run pytest
 
 on:
@@ -9,26 +6,45 @@ on:
   pull_request:
     branches: [master]
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        # When changing this matrix, you have to change the "after_n_builds" parameter
+        # in the .github/codecov.yml file. It must match the number of builds being
+        # started considering the matrix. See the following links for more information:
+        # https://docs.codecov.com/docs/notifications#preventing-notifications-until-after-n-builds
+        # https://docs.codecov.com/docs/pull-request-comments#after_n_builds
+        icalendar-version:
+          - "5" # means (>=5.0.0,<6.0.0)
+          - "6" # means (>=6.0.0,<7.0.0)
 
     steps:
-      - uses: actions/checkout@v4
-      - name: Set up Python 3.9
+      - name: "Checkout repository"
+        uses: actions/checkout@v4
+
+      - name: "Set up Python 3.9"
         uses: actions/setup-python@v5
         with:
-          python-version: '3.9'
-      - name: Install dependencies
+          python-version: "3.9"
+
+      - name: "Install poetry"
+        uses: abatilo/actions-poetry@v3
+        with:
+          poetry-version: "2.0.1"
+
+      - name: "Install icalendar ${{ matrix.icalendar-version }} and other dependencies"
         run: |
-          python -m pip install --upgrade pip
-          pip install poetry==2.0.1
-          poetry install
-      - name: Test with pytest
+          poetry add icalendar~=${{ matrix.icalendar-version }}.0 --no-interaction
+
+      - name: "Test with pytest"
         run: |
           poetry run coverage run test.py
           poetry run coverage xml
-      - name: 'Upload coverage to Codecov'
+
+      - name: "Upload coverage to Codecov"
         uses: codecov/codecov-action@v5
-        with:
-          fail_ci_if_error: false
diff --git a/README.md b/README.md
index e717e9f..0b028fd 100644
--- a/README.md
+++ b/README.md
@@ -6,9 +6,9 @@ Simple Python 3 library to download, parse and query iCal sources.
 
 ## Build info
 
-last push: ![run pytest](https://github.com/jazzband/icalevents/actions/workflows/python-test.yml/badge.svg)
+last push: [![Run pytest](https://github.com/jazzband/icalevents/actions/workflows/tests.yml/badge.svg)](https://github.com/jazzband/icalevents/actions/workflows/tests.yml)
 
-master: [![Run pytest](https://github.com/jazzband/icalevents/actions/workflows/python-test.yml/badge.svg?branch=master)](https://github.com/jazzband/icalevents/actions/workflows/python-test.yml)
+master: [![Run pytest](https://github.com/jazzband/icalevents/actions/workflows/tests.yml/badge.svg?branch=master)](https://github.com/jazzband/icalevents/actions/workflows/tests.yml?query=branch%3Amaster++)
 
 ## Documentation
 
diff --git a/icalevents/icalparser.py b/icalevents/icalparser.py
index 55a8857..98289d3 100644
--- a/icalevents/icalparser.py
+++ b/icalevents/icalparser.py
@@ -2,25 +2,25 @@
 Parse iCal data to Events.
 """
 
-# for UID generation
-from faulthandler import is_enabled
+from datetime import datetime, timedelta, date
+from importlib.metadata import version
 from random import randint
-from datetime import datetime, timedelta, date, tzinfo
 from typing import Optional
+from uuid import uuid4
 
 from dateutil.rrule import rrulestr
 from dateutil.tz import UTC, gettz
-
 from icalendar import Calendar
 from icalendar.prop import vDDDLists, vText
-from uuid import uuid4
-
-from icalendar import use_pytz
-from icalendar.timezone.windows_to_olson import WINDOWS_TO_OLSON
 from pytz import timezone
 
+if version("icalendar") >= "6.0":
+    from icalendar import use_pytz
+    from icalendar.timezone.windows_to_olson import WINDOWS_TO_OLSON
 
-use_pytz()
+    use_pytz()
+else:
+    from icalendar.windows_to_olson import WINDOWS_TO_OLSON
 
 
 def now():
diff --git a/poetry.lock b/poetry.lock
index 90bb93b..3e6a4a1 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -221,14 +221,14 @@ six = ">=1.8.0"
 
 [[package]]
 name = "icalendar"
-version = "6.1.0"
+version = "6.1.1"
 description = "iCalendar parser/generator"
 optional = false
 python-versions = ">=3.8"
 groups = ["main"]
 files = [
-    {file = "icalendar-6.1.0-py3-none-any.whl", hash = "sha256:46c09b774a6e6948495dafcb166dc15135c8259d0ae25491f154cbc822714b69"},
-    {file = "icalendar-6.1.0.tar.gz", hash = "sha256:43c2db8632959d634f4e48f6e6131e706bf2cdddad488cf0b72fda079b796bad"},
+    {file = "icalendar-6.1.1-py3-none-any.whl", hash = "sha256:accf3a4be9a1f89bad00e0bf14103b02cd9b02dcb9b4258eb717f39d24cf58e9"},
+    {file = "icalendar-6.1.1.tar.gz", hash = "sha256:2c44355a8f006de5ae73fa3f022a1cbe2a0de6b1607ce8879739eb887c4f3471"},
 ]
 
 [package.dependencies]
@@ -717,4 +717,4 @@ files = [
 [metadata]
 lock-version = "2.1"
 python-versions = ">=3.9"
-content-hash = "8fc64de4f55b234589828215b2dca5a673f1772127f00a7eb4708a634ed109a4"
+content-hash = "21197e64a2880ca0c132fb21c5fc84e6096b4586e5cfc41a31a44eebd08fe237"
diff --git a/pyproject.toml b/pyproject.toml
index a08d5c4..f819353 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ license = "MIT"
 requires-python = ">=3.9"
 
 dependencies = [
-    "icalendar (~=6.0)",
+    "icalendar (>=5.0.0)",
     "python-dateutil (~=2.9)",
     "pytz (>=2024.2)",
     "urllib3 (>=1.26.5)",