I am trying to upgrade our current Solr from 4.x to 7.7.2. We have a Drupal 7 installation, that has the apachesolr-7.x-1.6 module installed. I have been researching but cannot find any information, will this work? Is this compatible? My research tells me that Drupal 7 can only work with 7.7.2, but it doesn't indicate which module to use. I see the search_api module, but I'm hoping I don't have to upgrade the module, as that would increase complexity to our change package.