Oscommerce "Who's Online" and "Sessions"' problem with upgrade to PHP 5.6.37

I have a site here: [login to view URL] It has been on PHP 5.3.3 and I have switched it to PHP 5.6.37 Everything works fine but for ONE thing. The [login to view URL] seems to have an old outdated way of connecting to the data base that is causing a problem. It is trying to connect with if (STORE_SESSIONS == 'mysql') when I think it should be ('mysqli') ALSO in the [login to view URL] file the same thing seems to be going on. PROBLEMS are 1) in the admin side of oscommerce the Whois Online addon works but sometimes when you click on one of the listings it throws you out and makes you log in again and does not show you the information. 2) The sessions are logged in the sessions table in the database but they NEVER are deleted. Last week over 1,400 of them were in the table and of course I deleted them so that it can start over. Was thinking that they should be deleted after 60 minutes (as that is what I have the set at in the admin.) So (as I understand it) these files ([login to view URL] and [login to view URL] in the front end and back end) need to be updated to PHP 5.6.37 code. If I understand it right should be a quick fix. Can anyone help me on this project? Thanks Leon