Add a new 2960X with different IOS version but same stack protocol version to existing stack

[shanilkumar2003]

I need to add one new 2960x switch to an existing production stack of 2960x. existing stack has got different IOS than new switch ,but stack protocol version  (maj.min) looks the same. do I need to upgrade the IOS or will it work with different IOS if I add to existing stack , please help
 
Existing Stack
===========

System image file is "flash:/c2960x-universalk9-mz.150-2a.EX5.bin"

Switch Ports Model              SW Version            SW Image                
------ ----- -----              ----------            ----------              
*    1 52    WS-C2960X-48FPS-L  15.0(2a)EX5           C2960X-UNIVERSALK9-M    
     2 52    WS-C2960X-48FPS-L  15.0(2a)EX5           C2960X-UNIVERSALK9-M    
     3 28    WS-C2960X-24PS-L   15.0(2a)EX5           C2960X-UNIVERSALK9-M

[Sergey Lisitsin]

shanilkumar2003,

Yes, the requirement is to have all the stack members on the same version of IOS code.

[Sergey Lisitsin]

You have two choices here: either to downgrade the new member's IOS version to what is running on the stack or to upgrade the stack version and connect the new member.

[Seb Rupik]

Hi there,

Take a look at the command: boot auto-copy-sw

...this should copy the current stack image to the newly joining member.

In reality I have never seen this work correctly, so I always configure the new switch with the same images that is running on the stack it is about to join.

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960x/software/15-0_2_EX/stack_manager/configuration_guide/b_stck_152ex_2960-x_cg/b_stck_152ex_2960-x_cg_chapter_010.html#con_1189959 

Cheers,

Seb.

[Sergey Lisitsin]

Yes, I think general practice is to upgrade/downgrade to the same version before joining a new member. Much safer option.

[Mark Malone]

If the major and minor numbers work it will stack ok , they dont need to be exactly the same but these must match
It is good practice to have them match exactly though for feature capability

[rupesh00111]

Find below checklist
1. Make new switch iOS same as stack iOS
2. Make new switch stack priority lowest
3. When connecting new switch in stack make sure it is power off , then do stack cabling , once cabling is complete poweron the new switch.