In general you can only jump 4 Junos versions, which is the number before the decimal point (12 to 16) for this example.
But this also assumes you are running the long term release of the running chain which will be either a 3 or 4 after the decimal depending on the year.
The details are logged in the release notes for the target version of the upgrade. So you would start by reviewing the upgrade section of the release notes on junos 16.4 to see what the upgrade requirements are. If moving up from 12.2 is supported you go from there. Or you might need to go to 12.3 first. Or might need to move back to 15.3 as the first jump.
Then repeat the process for the next step in the process going up from the new version.
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Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
http://puluka.com/home------------------------------
Original Message:
Sent: 10-25-2022 04:01
From: Unknown User
Subject: MX480 upgrade path
Hello!
i have mx480 with 2xRE-S-1800X4-16G-S , JunOS 12.2R2.5.
I need to update it to the latest recommended junOS for MX480 (20.4R3-S4), but i can't install right away the necessary junOS due to incompatibility version. Is there any sequential order for installing versions to the one I need?