Refs #12990 -- Bumped mysqlclient requirement to >= 1.4.0.

MySQLdb.constants.FIELD_TYPE.JSON was added in mysqlclient 1.4.0rc2.

django/db/backends/mysql/base.py

@@ -32,8 +32,8 @@ from .schema import DatabaseSchemaEditor                    # isort:skip
 from .validation import DatabaseValidation                  # isort:skip
 
 version = Database.version_info
-if version < (1, 3, 13):
-    raise ImproperlyConfigured('mysqlclient 1.3.13 or newer is required; you have %s.' % Database.__version__)
+if version < (1, 4, 0):
+    raise ImproperlyConfigured('mysqlclient 1.4.0 or newer is required; you have %s.' % Database.__version__)
 
 
 # MySQLdb returns TIME columns as timedelta -- they are more like timedelta in

docs/ref/databases.txt

@@ -361,7 +361,7 @@ Connector/Python includes `its own`_.
 mysqlclient
 ~~~~~~~~~~~
 
-Django requires `mysqlclient`_ 1.3.13 or later.
+Django requires `mysqlclient`_ 1.4.0 or later.
 
 MySQL Connector/Python
 ~~~~~~~~~~~~~~~~~~~~~~

docs/releases/3.1.txt

@@ -690,6 +690,9 @@ Miscellaneous
 * The auto-reloader no longer monitors changes in built-in Django translation
   files.
 
+* The minimum supported version of ``mysqlclient`` is increased from 1.3.13 to
+  1.4.0.
+
 .. _deprecated-features-3.1:
 
 Features deprecated in 3.1

tests/requirements/mysql.txt

@@ -1 +1 @@
-mysqlclient >= 1.3.13
+mysqlclient >= 1.4.0