Hi you can do the whole stack in one with archive command , mixed stack doesnt matter once there running same version
Upgrading the Cisco IOS Software Release on a Stack
FlexStack has the capability to upgrade all members with a single command. A single command eases the operational burden on the network administrator. The command to initiate an upgrade takes place on the master. The master makes sure that each member is properly upgraded.
The Cisco IOS Software CLI command to upgrade a FlexStack stack
“archive download-sw [options] <source-file>.”
The default behavior is to upgrade all members.
The options for the ‘archive download-sw’ command allow for detailed control of the upgrade. Use the options to update only a single member instead of the entire stack or to reload the stack after the upgrade is successful instead of having the reboot be an extra step for the network admin.
The “source file” is a tar file downloaded from Cisco.com called an image file. The tar file can be copied over the network using Trivial File Transfer Protocol (TFTP) or FTP. The most common and recommended way to upgrade the stack of switches is using TFTP. The network admin should copy the tar file with the desired Cisco IOS Software image to a TFTP server in the network. In the ‘archive download-sw‘ command, use the IP address of the TFTP server and the name of the image file as the source file. No destination file name is necessary.
Here is an example of using the ‘archive download-sw‘ command to upgrade a stack of Cisco Catalyst 2960-S switches. Notice that the number of members in the stack is not relevant to this command. By default all members are upgraded unless the network admin uses the options to do otherwise. The TFTP IP address is 192.168.1.1, and the tar file name is c2960s-universalk9-tar.122.53.SE.tar
Switch# archive download-sw tftp://192.168.1.1/c2960s-universalk9-tar.122.53.SE.tar
If a network connection is not possible, the stack can be upgraded by reading the image file from a USB Flash drive. A USB Flash drive must be inserted in the USB A slot on the front of the switch. The tar file containing the Cisco Catalyst 2960-S Cisco IOS Software image must be on the Flash drive. The USB Flash drive is referenced by the member it was inserted into. If the USB Flash driver was inserted into member 2, then it will be referenced as “usbflash2:.” Use the same download command used in the preceding example, except this time point to the USB Flash instead of the TFTP server:
Switch# archive download-sw usbflash2:c2960s-universalk9-tar.122.53.SE.tar
The Cisco IOS Software CLI command “archive download-sw …” is very flexible and yet simple to use. It can retrieve source images from multiple locations (for example, FTP, TFTP, Flash). The command allows for detailed control of the upgrade process. For more information about the “archive download-sw” command, see the Cisco Catalyst 2960-S software configuration guide on Cisco.com.
