All the text (including window title bar, title, button text, etc) can be altered in Advanced Agent Settings in Manage > Agents > Agent Configuration > Advanced Agent Settings. These should persist fine through upgrades.
The settings for Notify/Cancel (UI.NOTIFY_CANCEL), Notify (UI.MONITOR) and Notify/Block (UI.PREVENT) are separated, specifically for Notify/Block you'll want to look at;
UI.PREVENT_MSG_TITLE.str
UI.PREVENT_TITLEBAR.str
The below settings apply to all notifications;
'OK' button text - UI.BUTTON_OK.str
'OK to All button text - UI.BUTTON_OKTOALL.str
Text for justification field (Default 'Others:) - UI.USERINPUT_PROMPT.str