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.
The ModelsToArrayTransformer has been renamed to LegacyModelsToArrayTransformer. ModelsToArrayTransformer should be only be used with SF2.7+