That is correct because the file you are using there has the name as Bootable_UCSInstall_UCCX_11_0_1_UCOS_11.0.1.10000-75.sgn which makes it useful for fresh installation and not for upgrade purpose. If you want to use this file for upgrade, then simply remove the Bootable_ and rename it like below and it will work then:
UCSInstall_UCCX_11_0_1_UCOS_11.0.1.10000-75.sgn.iso
Regards
Deepak