Upgrading from 16.9.2 to 17.9.5 (Catalyst 9300-48P)

[bboyce]

Has anybody upgraded a Catalyst 9300-48P (or similar) from 16.9.2 straight to 17.9.5? Is it okay to go direct, or do I need to do a stepped upgrade? This section from the release notes leads me to believe all will be good - but I wanted to confirm before going forward. This upgrade is the oldest IOS I'll be coming from, and I've already upgraded several from 17.3.4 with a scheduled, self deleting EEM applet, which has proven to be no issue.

I'll also need to go to 17.9.5 from 16.12.4, 17.3.1 & 17.5.1 but I figured as long as the oldest IOS XE version could go straight to the new target IOS, all would be good with the others.

If this belongs in another thread, my apologies, I am just getting used to using the forum.

[RAdamWilliams]

I've seen no issues going from any 16 version to any 17 version.

[Leo Laohoo · Accepted solution]

Read the Release Notes of 17.9.5, particularly the Open and Resolved Caveat sections.

Upgrading from 16.X.X to 17.9.X is fine but expect a downtime of about 14 minutes due to a mandatory micro-code upgrade. 

[inghugoadmin]

Hello, what about the Rommon version, do I have to upgrade to 17.9.2r or something around that?

From IOS 16.12.8 to 17.9.5

From Rommon 16.12.2r to ??

[Leo Laohoo]

For switches (and only switches!), the ROMMON will automatically upgrade.

For routers, upgrade to an intermediate version, like 17.9.X, before going to 17.12.X (and later).  This important step is undocumented.  The reason is routers need to be running ROMMON version 17.5.1r (or later):  Cisco has rolled ROMMON version 17.5.1r into 17.9.X but did not roll it into 17.12.X.  

Router upgrading direct, from 17.6.X (or earlier) to 17.12.X (and later), will go into a boot-crash-loop.

[balaji.bandi]

Has anybody upgraded a Catalyst 9300-48P (or similar) from 16.9.2 straight to 17.9.5?

many in day to day operation. as other suggested its straight upgrade, and as @Leo Laohoo suggested required micro code upgrade.

if this is stack  my personal experience take 15-20min for the whole stack to come online.