Something to check into:
I just updated an established cacti installation from 0.8.7g to 0.8.8b and noticed that I could not view the Plugin Management menu option in the left hand navigation.
I checked my particular user permissions in User Management and found that I had all Realm Permissions but Plugin Management checked. Enabling it presented the missing menu option.
Same behavior occurred when I enabled the Aggregate plugin (no realm permissions) - once enabled I have the options.
The actual 'admin' account appears to have these all enabled by default. It makes sense that non-admin accounts would not be granted the new permissions. It's just disorienting when you're used to doing everything with your daily use account.
TL;DR: Check your user account permissions. If you're using something other than the default admin account, then you may need to grant yourself some permissions in order to see new features.