Merge pull request #7201 from readthedocs/davidfischer/feature-flag-latest-sphinx

Feature flag for using latest Sphinx

Author: ericholscher

readthedocs/doc_builder/python_environments.py

@@ -352,12 +352,10 @@ def install_core_requirements(self):
                 ),
             )
         else:
-            # We will assume semver here and only automate up to the next
-            # backward incompatible release: 2.x
             requirements.extend([
                 self.project.get_feature_value(
                     Feature.USE_SPHINX_LATEST,
-                    positive='sphinx<2',
+                    positive='sphinx',
                     negative='sphinx<2',
                 ),
                 'sphinx-rtd-theme<0.5',