Allied Telesis AT-S63 - Manual (Page 45)

AT-S63 Stack Command Line User’s Guide
Section I: Basic Operations 45
Upgrading the AT-S63 Management Software
The AT-9400 Switch must have Version 3.0.0 or later of the AT-S63
Management Software to be a member of a stack.
To update the management software on an existing stack for versions
after Version 3.0.0, you must disconnect the stacking cables and update
the switches individually, either locally through the Terminal Port on the
units or over the network using a TFTP server. You reconnect the stacking
cables after the management software on all of the switches has been
updated.
Note
The switches of a stack must use the same version of the
management software.