Force uploads of new media to use https (not http) urls

A few months ago I switched my multisite to https by editing wp-config.php and .htaccess. I now need to get newly imported images to load as https instead of http (especially since the srcset doesn't seem to be working with my 4.4 update). I was going to do what this article suggests (https://wordpress.org/support/topic/force-https-or-relative-urls-for-media-in-posts) but the WordPress code in ms-blogs.php line (38ish) looks different in my current version of WordPress (4.4) so I thought it best to ask if this was advisable or if I should go another route.