6 files declare their use of Drupal8State in Rocket.Chat 8.2

Channel.php in modules/rocket_chat_api/src/RocketChat/Element/Channel.php

GroupChannel.php in modules/rocket_chat_group/src/Plugin/Field/FieldType/GroupChannel.php

moduleHelper.php in modules/rocket_chat_group/src/RocketChat/moduleHelper.php

RocketChatChannelBlock.php in modules/rocket_chat_group/src/Plugin/Block/RocketChatChannelBlock.php

RocketChatGroupHelper.php in src/Form/RocketChatGroupHelper.php

RocketChatSettingsForm.php in src/Form/RocketChatSettingsForm.php

Contains \Drupal\rocket_chat\Form\RocketChatSettingsForm.