Switch 3850 ios version issue

[Leftz]

Hi Cisco switch 3850 has the below output using show version. The ios usually is like 16.x, 17.x. Why it show 03.06.06E? 

Anyone would like to explain? Thank you!

Switch Ports Model SW Version SW Image Mode
------ ----- ----- ---------- ---------- ----
1 32 WS-C3850-24P 03.06.06E cat3k_caa-universalk9 INSTALL

[balaji.bandi · Accepted solution]

 03.06.06E  - this denali  IOS XE  version cisco released, then moved to 16.X  version.

16.X also have denali and other IOS XE versions available

[Leftz · Accepted solution]

Thank you for your reply. 

I notice in another switch with the same model 3850 and same image, why it has different SW Version expression? its 16.3.5b. Please see the below. Do they both have the same eol? Thanks

Switch Ports Model SW Version SW Image Mode
------ ----- ----- ---------- ---------- ----
* 1 32 WS-C3850-24P 16.3.5b CAT3K_CAA-UNIVERSALK9 INSTALL

[balaji.bandi · Accepted solution]

as I mentioned initial release for 3850 was Denali 3. X version, later cisco moved to 16. X jump, and so on.

[Leo Laohoo · Accepted solution]

3.6.X may be old but it is one of the most stable IOS-XE version for 3650/3850. 

You can get years of uptime with 3.6.X which you won't be able to achieve with 16.X.X.