diff --git a/.gitignore b/.gitignore
index a9a908e..89531ed 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,3 +28,5 @@
 /OWSLib-0.25.0.tar.gz
 /OWSLib-0.26.0.tar.gz
 /OWSLib-0.27.2.tar.gz
+/OWSLib-0.28.0.tar.gz
+/OWSLib-0.28.1.tar.gz
diff --git a/python-OWSLib.spec b/python-OWSLib.spec
index be0e11b..a646079 100644
--- a/python-OWSLib.spec
+++ b/python-OWSLib.spec
@@ -5,7 +5,7 @@
 %bcond_without doc_pdf
 
 Name:           python-OWSLib
-Version:        0.27.2
+Version:        0.28.1
 Release:        %autorelease
 Summary:        Client library for OGC web services
 
@@ -65,7 +65,10 @@ sed -r -i 's/[-]-cov[^[:blank:]]*[[:blank:]][^[[:blank:]]+//g' tox.ini
 #
 # Don’t generate twine dependency, which is just for the upstream maintainer
 # uploading to PyPI.
-sed -r '/^(flake8|pytest-cov|pandoc|coverage|coveralls|twine)\b/d' \
+sed -r -e '/^(flake8|pytest-cov|pandoc|coverage|coveralls|twine)\b/d' \
+%if %{without doc_pdf}
+    -e '/^(ipykernel|nbconvert|.*sphinx)/d' \
+%endif
     requirements-dev.txt | tee requirements-dev-filtered.txt
 
 # We don’t need shebangs in the examples. The pattern of selecting files
@@ -83,7 +86,7 @@ echo 'nbsphinx_allow_errors = True' >> docs/conf.py
 
 
 %generate_buildrequires
-%pyproject_buildrequires -r requirements-dev-filtered.txt
+%pyproject_buildrequires requirements-dev-filtered.txt
 
 
 %build
diff --git a/sources b/sources
index 3d2520a..6ddf3e6 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-SHA512 (OWSLib-0.27.2.tar.gz) = 02c70731ef92783d53b8f0dff2cec7d28d14ac08b0a4b5090183f9eacf156d539c823fcd2ae480c07447e901697de498cdf2aaf27c8b6d46fa4cf8eb3679ceee
+SHA512 (OWSLib-0.28.1.tar.gz) = bd62a5e371e64e0e256cc83d2f044294c20965f6b107b0dd9074ac752971620f01af4c7fc9a82e43dc81e71a6a36696b75403012841c28925b017d9c47b2d4a5