diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 7ca3906..e55622e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -57,11 +57,11 @@ jobs:
     strategy:
       matrix:
         python:
-          - "3.8"
           - "3.9"
           - "3.10"
           - "3.11"
-          - "3.12"  # newest Python that is stable
+          - "3.12"
+          - "3.13"  # newest Python that is stable          
         platform:
         - ubuntu-latest
         # - macos-latest
@@ -79,8 +79,7 @@ jobs:
       - name: Run tests
         run: >-
           pipx run --python '${{ steps.setup-python.outputs.python-path }}'
-          tox --installpkg '${{ needs.prepare.outputs.wheel-distribution }}'
-          -- -rFEx --durations 10 --color yes  # pytest args
+          tox --develop
       # - name: Generate coverage report
       #   run: pipx run coverage lcov -o coverage.lcov
       # - name: Upload partial coverage report
@@ -96,11 +95,11 @@ jobs:
     strategy:
       matrix:
         python:
-          - "3.8"
           - "3.9"
           - "3.10"
           - "3.11"
-          - "3.12"  # newest Python that is stable
+          - "3.12"
+          - "3.13"  # newest Python that is stable
         platform:
         - ubuntu-latest
         # - macos-latest
@@ -118,18 +117,18 @@ jobs:
       - name: Run tests
         run: >-
           pipx run --python '${{ steps.setup-python.outputs.python-path }}'
-          tox -e lint --installpkg '${{ needs.prepare.outputs.wheel-distribution }}'
+          tox -e lint --develop
 
   typecheck:
     needs: prepare
     strategy:
       matrix:
         python:
-          - "3.8"
           - "3.9"
           - "3.10"
           - "3.11"
-          - "3.12"  # newest Python that is stable
+          - "3.12"
+          - "3.13"  # newest Python that is stable          
         platform:
         - ubuntu-latest
         # - macos-latest
@@ -147,7 +146,7 @@ jobs:
       - name: Run tests
         run: >-
           pipx run --python '${{ steps.setup-python.outputs.python-path }}'
-          tox -e typecheck --installpkg '${{ needs.prepare.outputs.wheel-distribution }}'
+          tox -e typecheck --develop
 
   finalize:
     needs: [test, lint, typecheck]
diff --git a/pyproject.toml b/pyproject.toml
index 85788e6..35d8840 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,7 +12,7 @@ version = "0.5.0"
 readme = "README.rst"
 license = "Apache-2.0"
 license-files = ["LICENSE"]
-requires-python = ">=3.8, < 3.13"
+requires-python = ">=3.9, < 3.14"
 dependencies = [
     "pydantic>=2.8.2",
     "pytz",
@@ -20,11 +20,11 @@ dependencies = [
 ]
 classifiers = [
     "Development Status :: 4 - Beta",
-    "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",    
 ]
 [project.urls]
     "Source code" = "https://github.com/flexiblepower/s2-ws-json-python"