Please delete this directory manually

After the database upgrade to 2.0.2, a warning came up asking to delete some subfolders manually. In this particular case it was:


Warning messages:

Warnings during the update: <br>Please delete this directory manually (eg. using your FTP software): /.../plugins/Referers
<br>Please delete this directory manually (eg. using your FTP software): /.../plugins/PDFReports 

Warnings during the update: <br>Please delete this directory manually (eg. using your FTP software): /.../libs/Smarty 
<br>Please delete this directory manually (eg. using your FTP software): /.../libs/Event

I haven’t found any reference to this on the piwik.org and that’s why I’m posting about it.

Why would this happen?

Thanks

we renamed some plugins and stopped using some libraries, so they can be safely deleted

Thanks.

BTW, I see more subfolders that are not present in 2.x. Does this means they can be deleted safely as well?