Fixed #18392 -- Changed default mysql encoding to "utf8mb4".

3 files changed, 21 insertions, 14 deletions

diff --git a/docs/ref/contrib/auth.txt b/docs/ref/contrib/auth.txt
index 103aff8e0b..3e1cdfd978 100644
--- a/docs/ref/contrib/auth.txt
+++ b/docs/ref/contrib/auth.txt
@@ -30,10 +30,7 @@ Fields
 
         The ``max_length`` should be sufficient for many use cases. If you need
         a longer length, please use a :ref:`custom user model
-        <specifying-custom-user-model>`. If you use MySQL with the ``utf8mb4``
-        encoding (recommended for proper Unicode support), specify at most
-        ``max_length=191`` because MySQL can only create unique indexes with
-        191 characters in that case by default.
+        <specifying-custom-user-model>`.
 
     .. attribute:: first_name
 
diff --git a/docs/ref/databases.txt b/docs/ref/databases.txt
index 73a67475fe..57e94140c2 100644
--- a/docs/ref/databases.txt
+++ b/docs/ref/databases.txt
@@ -517,7 +517,7 @@ You can `create your database`_ using the command-line tools and this SQL:
 
 .. code-block:: sql
 
-  CREATE DATABASE <dbname> CHARACTER SET utf8;
+  CREATE DATABASE <dbname> CHARACTER SET utf8mb4;
 
 This ensures all tables and columns will use UTF-8 by default.
 
@@ -542,21 +542,21 @@ Django doesn't provide an API to change them.
 .. _documented thoroughly: https://dev.mysql.com/doc/refman/en/charset.html
 
 By default, with a UTF-8 database, MySQL will use the
-``utf8_general_ci`` collation. This results in all string equality
+``utf8mb4_0900_ai_ci`` collation. This results in all string equality
 comparisons being done in a *case-insensitive* manner. That is, ``"Fred"`` and
 ``"freD"`` are considered equal at the database level. If you have a unique
 constraint on a field, it would be illegal to try to insert both ``"aa"`` and
 ``"AA"`` into the same column, since they compare as equal (and, hence,
 non-unique) with the default collation. If you want case-sensitive comparisons
 on a particular column or table, change the column or table to use the
-``utf8_bin`` collation.
+``utf8mb4_0900_as_cs`` collation.
 
 Please note that according to `MySQL Unicode Character Sets`_, comparisons for
-the ``utf8_general_ci`` collation are faster, but slightly less correct, than
-comparisons for ``utf8_unicode_ci``. If this is acceptable for your application,
-you should use ``utf8_general_ci`` because it is faster. If this is not acceptable
-(for example, if you require German dictionary order), use ``utf8_unicode_ci``
-because it is more accurate.
+the ``utf8mb4_general_ci`` collation are faster, but slightly less correct,
+than comparisons for ``utf8mb4_unicode_ci``. If this is acceptable for your
+application, you should use ``utf8mb4_general_ci`` because it is faster. If
+this is not acceptable (for example, if you require German dictionary order),
+use ``utf8mb4_unicode_ci`` because it is more accurate.
 
 .. _MySQL Unicode Character Sets: https://dev.mysql.com/doc/refman/en/charset-unicode-sets.html
 
@@ -602,7 +602,7 @@ Here's a sample configuration which uses a MySQL option file::
     database = NAME
     user = USER
     password = PASSWORD
-    default-character-set = utf8
+    default-character-set = utf8mb4
 
 Several other `MySQLdb connection options`_ may be useful, such as ``ssl``,
 ``init_command``, and ``sql_mode``.
diff --git a/docs/releases/5.2.txt b/docs/releases/5.2.txt
index a977e6c803..3cc71b7f68 100644
--- a/docs/releases/5.2.txt
+++ b/docs/releases/5.2.txt
@@ -174,7 +174,9 @@ CSRF
 Database backends
 ~~~~~~~~~~~~~~~~~
 
-* ...
+* MySQL connections now default to using the ``utf8mb4`` character set,
+  instead of ``utf8``, which is an alias for the deprecated character set
+  ``utf8mb3``.
 
 Decorators
 ~~~~~~~~~~
@@ -385,6 +387,14 @@ Dropped support for PostgreSQL 13
 Upstream support for PostgreSQL 13 ends in November 2025. Django 5.2 supports
 PostgreSQL 14 and higher.
 
+Changed MySQL connection character set default
+----------------------------------------------
+
+MySQL connections now default to using the ``utf8mb4`` character set, instead
+of ``utf8``, which is an alias for the deprecated character set ``utf8mb3``.
+``utf8mb3`` can be specified in the ``OPTIONS`` part of the ``DATABASES``
+setting, if needed for legacy databases.
+
 Miscellaneous
 -------------