DOC Add autologin token regeneration changes to 5.3 changelog

en/08_Changelogs/5.3.0.md

@@ -12,6 +12,7 @@ title: 5.3.0 (unreleased)
   - [Validation for elemental content blocks when saving individual blocks](#elemental-validation)
   - [Define scaffolded form fields for relations to `DataObject` models](#scaffolded-relation-formfields)
   - [Support for `JOIN` in SQL `UPDATE`](#sql-update-join)
+  - [Autologin token regeneration changes](#autologin-token-regeneration)
   - [Other new features](#other-new-features)
   - [API changes](#api-changes)
 - [Bug fixes](#bug-fixes)
@@ -109,6 +110,21 @@ The [`SQLUpdate`](api:SilverStripe\ORM\Queries\SQLUpdate) class now supports all
 
 This is particularly helpful if you need to update columns in one table to match values from another table.
 
+### Autologin token regeneration changes {#autologin-token-regeneration}
+
+The Autologin ('remember me') feature stores cookies in the user's browser to allow recreation of their session when it expires. Currently, one of the cookies is regenerated whenever a user's session is recreated. This can cause unexpected logouts in certain situations, and has minimal value from a security standpoint.
+
+In 5.3, the current behaviour is retained, but can be disabled via configuration:
+
+```yml
+SilverStripe\Security\RememberLoginHash:
+  replace_token_during_session_renewal: false
+```
+
+This will cause the token to be generated once during login, and not be regenerated during session renewal.
+
+From 6.0 onwards, tokens will never be regenerated during session renewal, and this configuration will be removed.
+
 ### Other new features
 
 - `silverstripe/linkfield` now has improved accessibility support for screen readers and keyboard navigation. Focus states have also been made consistent between keyboard and mouse interaction.
@@ -120,6 +136,9 @@ This is particularly helpful if you need to update columns in one table to match
 
 - Passing a non-array `$fields` argument to both [`FieldList::addFieldsToTab()`](api:SilverStripe\Forms\FieldList::addFieldsToTab()) and [`FieldList::removeFieldsFromTab()`](api:SilverStripe\Forms\FieldList::removeFieldsFromTab()) has been deprecated.
 - The [`BaseElement::getDescription()`](api:DNADesign\Elemental\Models\BaseElement::getDescription()) method has been deprecated. To update the description of elemental blocks, use the [`description`](api:DNADesign\Elemental\Models\BaseElement->description) configuration property and the localisation API.
+- The [`RememberLoginHash::renew()`](api:SilverStripe\Security\RememberLoginHash::renew()) method has been deprecated without replacement, since the associated behaviour will be removed in 6.0.
+  - The `onAfterRenewToken` extension point within this method will likely be replaced with a new extension point in 6.0.
+- The [`RememberLoginHash.replace_token_during_session_renewal`](api:SilverStripe\Security\RememberLoginHash->replace_token_during_session_renewal) configuration property has been added to allow disabling token regeneration during session renewal. This property will be removed in 6.0.
 
 ## Bug fixes