remove deprecated config.from_json

CHANGES.rst

@@ -10,6 +10,8 @@ Unreleased
 -   Remove previously deprecated code. :pr:`4337`
 
     -   The CLI does not pass ``script_info`` to app factory functions.
+    -   ``config.from_json`` is replaced by
+        ``config.from_file(name, load=json.load)``.
 
 
 Version 2.0.2

src/flask/config.py

@@ -176,6 +176,9 @@ class Config(dict):
 
         .. code-block:: python
 
+            import json
+            app.config.from_file("config.json", load=json.load)
+
             import toml
             app.config.from_file("config.toml", load=toml.load)
 
@@ -204,32 +207,6 @@ class Config(dict):
 
         return self.from_mapping(obj)
 
-    def from_json(self, filename: str, silent: bool = False) -> bool:
-        """Update the values in the config from a JSON file. The loaded
-        data is passed to the :meth:`from_mapping` method.
-
-        :param filename: The path to the JSON file. This can be an
-            absolute path or relative to the config root path.
-        :param silent: Ignore the file if it doesn't exist.
-        :return: ``True`` if the file was loaded successfully.
-
-        .. deprecated:: 2.0.0
-            Will be removed in Flask 2.1. Use :meth:`from_file` instead.
-            This was removed early in 2.0.0, was added back in 2.0.1.
-
-        .. versionadded:: 0.11
-        """
-        import warnings
-        from . import json
-
-        warnings.warn(
-            "'from_json' is deprecated and will be removed in Flask"
-            " 2.1. Use 'from_file(path, json.load)' instead.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-        return self.from_file(filename, json.load, silent=silent)
-
     def from_mapping(
         self, mapping: t.Optional[t.Mapping[str, t.Any]] = None, **kwargs: t.Any
     ) -> bool: