I don't understand the problem. I just now tried it and it worked fine.
1. copied servers.ini to servers_backup.ini
2. copied servers.ini from where a copy is saved from when the prior version was installed.
3. press alt+E to open the serverlist's window
When I now look at the dropdown list, I now see the contents from the server list taken from the old version instead.
Are you wanting to merge the old contents in with the new, or just use the old version only?
Because if you're wanting to keep the old server list, that should happen unless during install you check the box next to the serverlist, which causes it to copy the brand new server list on top of servers.ini instead of leaving the old one there.