some features we need (e.g. READ POSITION long form) are only officially
available with LTO-5, but work on many LTO-4 drives, so move LTO-4 to
'best-effort' support.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Supported Hardware
------------------
-Proxmox Backup Server supports `Linear Tape-Open`_ generation 4 (LTO-4)
-or later.
+Proxmox Backup Server supports `Linear Tape-Open`_ generation 5 (LTO-5)
+or later and has best-effort support for generation 4 (LTO-4). While
+many LTO-4 systems are known to work, some might need firmware updates or
+do not implement necessary features to work with Proxmox Backup Server.
Tape changing is carried out using the SCSI Medium Changer protocol,
so all modern tape libraries should work.