Upgrade ISSU C6807-XL-6T same train release

[marzi]

Hi all

I know that upgrade a relase in ISSU mode on WS-C6807-XL-6T device is not advisable.
Anyway, My question is: if the upgrade is done inside the same release train could we have problem ?

for example:
from 15.5(1)SY8 to 15.5.1-SY12
or
from 15.5(1)SY1 to 15.5.1-SY12

The release 15.5.1-SY12 is the last suggested

Unfortunately, I haven't found appropriate documentation for 15.5(x)SY release, but only for major release train (16.x or 17.x or 18.x)
follow the link :

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst_standalones/b-in-service-software-upgrade-issu.html

Is there anyone who had experience in this case ?

thanks in advance 

Fabrizio

[Leo Laohoo · Accepted solution]

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@marzi wrote:
from 15.5(1)SY1 to 15.5.1-SY12

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Starting from 15.5(1)SY4, Sup6T and associated line cards require a mandatory and very manual FPGA upgrade.  This information is not easily picked up by reading the 15.5(1)SY release notes because it is a "footnote" in the Secure FPGA Support section of the Release Notes.  

ISSU, FSU/eFSU/xFSU does not support FPGA upgrade.  

However, if somebody still insist on IOS upgrade with ISSU, make sure to raise a proactive TAC Case because if-and-when the ISSU upgrade inevitably fails TAC should know how to action to take back control of the chassis.