diff --git a/.circleci/config.yml b/.circleci/config.yml
index bbfdd87fb8..a11ec433c8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -223,7 +223,8 @@ jobs:
             mkdir /logs
             . /opt/conda/etc/profile.d/conda.sh
             # Install
-            mamba env create
+            locale
+            mamba env create -n esmvaltool -f environment.yml
             conda activate esmvaltool
             pip install .[doc]
             # Log versions
@@ -231,6 +232,7 @@ jobs:
             conda env export | tee /logs/environment.yml
             pip freeze | tee /logs/requirements.txt
             # Test building documentation
+            locale
             MPLBACKEND=Agg sphinx-build -W doc doc/build
       - store_artifacts:
           path: /logs
@@ -238,9 +240,10 @@ jobs:
 workflows:
   commit:
     jobs:
-      - run_tests
-      - test_installation_from_source_develop_mode
-      - test_installation_from_source_test_mode
+      - build_documentation
+      #- run_tests
+      #- test_installation_from_source_develop_mode
+      #- test_installation_from_source_test_mode
 
   nightly:
     triggers:
diff --git a/doc/conf.py b/doc/conf.py
index 3bf62cee4e..9c9ceb77a6 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -78,6 +78,12 @@
     'autosummary': True,
 }
 
+# show locale
+import locale
+print("XXX")
+print(locale.getlocale())
+print(locale.getencoding())
+
 # Show type hints in function signature AND docstring
 autodoc_typehints = 'both'
 
diff --git a/environment.yml b/environment.yml
index cb38f4ce25..57921de345 100644
--- a/environment.yml
+++ b/environment.yml
@@ -8,7 +8,7 @@ dependencies:
   - cartopy
   - cf-units
   - cftime
-  - dask >=2025  # github.com/ESMValGroup/ESMValCore/issues/2503
+  - dask >=2025, <2025.4.0  # github.com/ESMValGroup/ESMValCore/issues/2503, github.com/ESMValGroup/ESMValCore/issues/2716
   - dask-jobqueue
   - distributed
   - esgf-pyclient >=0.3.1
@@ -36,7 +36,7 @@ dependencies:
   - psutil
   - py-cordex
   - pybtex
-  - python >=3.10
+  - python >=3.10,<3.13.3
   - python-stratify >=0.3
   - pyyaml
   - requests
diff --git a/pyproject.toml b/pyproject.toml
index 891614eab0..c0b098c610 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -34,7 +34,7 @@ dynamic = [
 ]
 dependencies = [
     "cartopy",
-    "cf-units",
+    # "cf-units",
     "dask[array,distributed]>=2025",  # ESMValCore/issues/2503
     "dask-jobqueue",
     "esgf-pyclient>=0.3.1",
@@ -45,7 +45,7 @@ dependencies = [
     "fire",
     "geopy",
     "humanfriendly",
-    "iris-grib>=0.20.0",  # github.com/ESMValGroup/ESMValCore/issues/2535
+    # "iris-grib>=0.20.0",  # github.com/ESMValGroup/ESMValCore/issues/2535
     "isodate>=0.7.0",
     "jinja2",
     "nc-time-axis",  # needed by iris.plot
@@ -63,7 +63,7 @@ dependencies = [
     "requests",
     "rich",
     "scipy>=1.6",
-    "scitools-iris>=3.11",  # 3.11 first to support Numpy 2 and Python 3.13
+    # "scitools-iris>=3.11",  # 3.11 first to support Numpy 2 and Python 3.13
     "shapely>=2.0.0",
     "stratify>=0.3",
     "yamale",
@@ -82,13 +82,14 @@ test = [
     "pytest-metadata>=1.5.1",
     "pytest-mock",
     "pytest-xdist",
-    "ESMValTool_sample_data==0.0.3",
+    # "ESMValTool_sample_data==0.0.3",
 ]
 doc = [
-    "autodocsumm>=0.2.2",
+    # https://github.com/ESMValGroup/ESMValCore/pull/2706
+    # "autodocsumm>=0.2.2",
+    # "nbsphinx>=0.9.7",  # github.com/ESMValGroup/ESMValCore/issues/2669
     "ipython<9.0",  # github.com/ESMValGroup/ESMValCore/issues/2680
-    "nbsphinx>=0.9.7",  # github.com/ESMValGroup/ESMValCore/issues/2669
-    "sphinx>=6.1.3",
+    "sphinx>=8.2.3",  # >=6.1.3",
     "pydata_sphinx_theme",
 ]
 develop = [