Call to undefined method SolrBaseQuery::getContext()

getContext() is not a function of class "", which gets called here:

/**
 * Implements hook_apachesolr_modify_query().
 */
function apachesolr_multilingual_apachesolr_query_alter($query) {
  global $language;

  $context = $query->getContext();
  $environment = apachesolr_multilingual_environment_load($context['env_id']);
  ...
}

This causes all search pages to break. The hook is invoked before executing a search query. As suggested in apachesolr.api.php we always should call
drupal_alter('apachesolr_query', $query); before executing a query.