PhpList no longer visible - upgrade?

Move website to a new server and now phplist is blank page (e.g., www.site.com/lists/admin and every other page)
Currently running 3.3.8. Going to upgrade to 3.6.15 and see if that corrects problem
BUT, there are no upgrade instructions. Do I just upgrade as new install? What about existing database?

You would need to be careful about the php versions between the two servers, make sure phpList supports both versions.

I assume you moved the database from the old server to the new server.

to upgrade, I usually rename the top directory to soomething like ‘lislts338’, and then install the new version into the lists directory.

if that woks, you can then copy the lists338/config/config.php to the new install (lists/config/config.php). you might want to make a backup copy of the new config.php file before replacing it… i.e. copy config.php to config.php.orig that way you can alway ‘undo’ moving the old config.php.

the first time you login to the new config with the old config.php, it will ask you if you want to update your database. say ‘yes’.

Thank you for your response. But already solved (forgot about this post).
I backup up everything, uploaded the most current version, ran upgrade and all well.
Thanx again