Class changes

What changed
How it changed
Magento\Authorization\Model\Role::$_cacheTag
[protected] Property has been added.
Magento\Catalog\Model\Category::getCacheTags
[public] Method has been added.
Magento\Catalog\Model\Product::getCacheTags
[public] Method has been added.
Magento\Framework\Stdlib\Cookie\CookieMetadata::KEY_SAME_SITE
Constant has been added.
Magento\Framework\Stdlib\Cookie\CookieMetadata::getSameSite
[public] Method has been added.
Magento\Framework\Stdlib\Cookie\CookieMetadata::setSameSite
[public] Method has been added.
Magento\User\Model\User::$_cacheTag
[protected] Property has been added.

Interface changes

What changed
How it changed
Magento\Catalog\Api\ProductAttributeOptionUpdateInterface
Interface was added.
Magento\Eav\Api\AttributeOptionUpdateInterface
Interface was added.

Database changes

What changed
How it changed
login_as_customer_assistance_allowed
Table was added
media_gallery_asset/MEDIA_GALLERY_ID_PATH_TITLE_CONTENT_TYPE_WIDTH_HEIGHT
Unique key was removed
media_gallery_asset/constraint
Module db schema whitelist reduced (media_gallery_asset/constraint).

System changes

What changed
How it changed
checkout/cart/enable_clear_shopping_cart
A field-node was added
system.xml
System configuration file was added

Xsd changes

What changed
How it changed
maxIdleTime
An optional attribute was added
onlySpawnWhenMessageAvailable
An optional attribute was added
sleep
An optional attribute was added

Class API membership changes

What changed
How it changed
Magento\Framework\View\Page\Builder
Class was added.
Magento\SalesRule\Model\Validator
Class was added.