Juniper JUNOS OS 10.4 - RELEASE NOTES REV 6 Release Note page 193

Upgrade and Downgrade Instructions for Junos OS Release 10.4 for SRX Series Services Gateways and J Series Services Routers
10.0 or 9.3. To downgrade from Release 10.4 to 8.5, you first need to downgrade to 10.0
or 9.3, and then perform a second downgrade to Release 8.5.
For upgrades and downgrades to or from a non-EEOL release, the current policy is that
you can upgrade and downgrade by no more than three releases at a time. This policy
remains unchanged.
For more information on EEOL releases and to review a list of EEOL releases, see
.
http://www.juniper.net/support/eol/junos.html
Copyright © 2011, Juniper Networks, Inc. 193