You will need to follow the dependencies upgrade instructions.
If you have implemented a custom datagrid builder, you must adapt the signature of its addFilter method to match the one in DatagridBuilderInterface again.
CSS class sonata-autocomplete-dropdown-item is not automatically added to dropdown autocomplete item in sonata_type_model_autocomplete, use option dropdown_item_css_class to set the CSS class of dropdown item.
sonata_wrapper block was moved and is now inside the .wrapper div of admin lte theme.
The inline validation has been migrating to CoreBundle. Just rename Sonata\AdminBundle\Validator\ErrorElement to Sonata\CoreBundle\Validator\ErrorElement
AdminLTE version 2 has been integrated, this should work out of the box if you havn't change templates. If not you can review the upgrade guide here : http://almsaeedstudio.com/themes/AdminLTE/documentation/index.html#upgrade
In order to fix deprecated issue by spiting SecurityContextInterface, AclSecurityHandler constructor got a new argument.
If you're using a custom implementation of sonata.admin.route_loader service, make sure to provide an array as 2nd argument since the type for this argument is now hinted to array.