upgrading ISR IOS-XE router to latest recommended version

[EdvinasKairys11982]

I want to upgrade to newest recommended Bengaluru-17.6.3a(MD) version from this one: 16.09.03.

the hardware i'm using is: ISR4451-X/K9 

I know that it should be quite easy, just in configure mode enter: boot system bootflash:xxx.bin and reload.

The main question is what to do with ROMMON, currently i've ROMMON version 16.9(1r). In the release notes it's written, that the ROMMON version with new soft recommended to be: 16.12(2r).

Do i need manually update it, or it goes automatically with IOS-XE Software update ? In Release notes its said:

"From Cisco IOS XE release 17.6.1 onwards, the ROMMON image will not be released as a standalone package, and will be packaged with the IOS XE image." - by this I understand, that the rommon should automatically upgrade itself while upgrading IOS-XE software.

Do i'm correct ?

Also, what about CPLD upgrade ? do you ever need that ? In manuals i see no information whether it's needed or no.. i'm using ths one: 16092742, and recommended is: 15010638, wtf..

Any other tips for upgrading the IOS-XE ? Thanks

[balaji.bandi]

Personally i would go with - 17.3.5 (that is widly used and stable) until you have any reason for go 17.6.2

read the release notes:

https://www.cisco.com/c/en/us/td/docs/routers/access/4400/release/xe-17-3/isr4k-rel-notes-xe-17-3.html

[Leo Laohoo]

A router is the most critical component of a network.  And every network admin wants a stable and reliable network:  Upgrade to the latest 16.9.X and do not be tempted to upgrade to 16.10.X and newer (because it is not worth the pain and suffering).

[EdvinasKairys11982]

thank you for your comments @balaji.bandi @Leo Laohoo .

The main reason for upgrade to have Telemetry transport GRPC Dial-out function enabled. So it started to be available from 16.10.  Thanks for warning about 16.10. I guess the main reason to avoid upgrade is cisco smart licensing. I will postpone a little bit and think about it more.