I've never used an archive backup, and I'm not sure if a v11 archive backup can be un-archived by a different version, and I don't know if it's encrypted whether that's an issue. If you really want answers to using archive backups, let me know.
The simplest way to get a copy of another database is to :
1) Shut down the database engine cleanly
2) Copy the database file to another location
If you don't want to stop the database engine, you can take an image backup, which will include a database file and a transaction log.
If it's a v11 database file, you should still be able to start it using the v16 engine. If it's encrypted, you'll need to specify the encryption key.
Reg