diff --git a/docs/client_advanced.rst b/docs/client_advanced.rst
index 1d3e958d8d9..e8f016a96f0 100644
--- a/docs/client_advanced.rst
+++ b/docs/client_advanced.rst
@@ -645,15 +645,15 @@ on this.
 Character Set Detection
 -----------------------
 
-If you encounter a :exc:`UnicodeDecodeError` when using :meth:`ClientResponse.text()`
-this may be because the response does not include the charset needed
-to decode the body.
+If you encounter an 'Automatic charset detection will be removed' warning
+when using :meth:`ClientResponse.text()` this may be because the response
+does not include the charset needed to decode the body.
 
 If you know the correct encoding for a request, you can simply specify
 the encoding as a parameter (e.g. ``resp.text("windows-1252")``).
 
 Alternatively, :class:`ClientSession` accepts a ``fallback_charset_resolver`` parameter which
-can be used to introduce charset guessing functionality. When a charset is not found
+can be used to reintroduce charset guessing functionality. When a charset is not found
 in the Content-Type header, this function will be called to get the charset encoding. For
 example, this can be used with the ``chardetng_py`` library.::
 
diff --git a/docs/client_reference.rst b/docs/client_reference.rst
index ce05be837cd..d1d877255d4 100644
--- a/docs/client_reference.rst
+++ b/docs/client_reference.rst
@@ -52,7 +52,7 @@ The client session supports the context manager protocol for self closing.
                          requote_redirect_url=False, \
                          trust_env=False, \
                          trace_configs=None, \
-                         fallback_charset_resolver=lambda r, b: "utf-8")
+                         fallback_charset_resolver=_chardet_resolver)
 
    The class for creating client sessions and making requests.
 
@@ -207,7 +207,9 @@ The client session supports the context manager protocol for self closing.
       the encoding parameter to :meth:`bytes.decode()`.
 
       This function will be called when the charset is not known (e.g. not specified in the
-      Content-Type header). The default function simply defaults to ``utf-8``.
+      Content-Type header). The default function in 3.8.6 calls chardetng
+      or charset-normaliser. In 3.9+ this be replaced with a function that
+      simply defaults to ``utf-8``.
 
       .. versionadded:: 3.8.6
 
@@ -1422,8 +1424,6 @@ Response object
                            (default).
 
 
-      :raises: :exc:`UnicodeDecodeError` if decoding fails. See also
-               :meth:`get_encoding`.
 
       .. note::
 
@@ -1438,6 +1438,7 @@ Response object
 
    .. method:: json(*, encoding=None, loads=json.loads, \
                       content_type='application/json')
+      :async:
 
       Read response's body as *JSON*, return :class:`dict` using
       specified *encoding* and *loader*. If data is not still available