text: import conda_helpers as ch
  
  from .api import install as plugin_install
  
  
  def _update_plugin(package_name):
      '''
      Update plugin (no user interface).
  
      .. versionadded:: 0.19
  
      Parameters
      ----------
      package_name : str, optional
          Conda MicroDrop plugin package name, e.g., `microdrop.mr-box-plugin`.
  
      Returns
      -------
      dict
          If plugin was updated successfully, output will *at least* contain
          items with the keys ``old_versions`` and ``new_versions``.
  
          If no update was available, output will *at least* contain an item with
          the key ``version`` and will **not** contain the keys ``old_versions``
          and ``new_versions``.
  
      Raises
      ------
      IOError
          If Conda update server cannot be reached, e.g., if there is no network
          connection available.
  
      See also
      --------
      _update_plugin_ui
      '''
      try:
          update_json_log = plugin_install(package_name)
      except RuntimeError, exception:
          if 'CondaHTTPError' in str(exception):
              raise IOError('Error accessing update server.')
          else:
              raise
  
      if update_json_log.get('success'):
          if 'actions' in update_json_log:
              # Plugin was updated successfully.
              # Display prompt indicating previous version
              # and new version.
              actions = update_json_log['actions']
              update_json_log['old_versions'] = actions.get('UNLINK', [])
              update_json_log['new_versions'] = actions.get('LINK', [])
          else:
              # No update available.
              version_dict = ch.package_version(package_name)
              update_json_log.update(version_dict)
          return update_json_log
  