I presently have 2811 with 'c2800nm-advipservicesk9-mz.124-15.T10.bin' ios.Now i want add FL-SRST-35 license for which i have to upgrade ios to 15.1 and upgrade DRAM and flash as required.But i am stuck in ios upgradation from 12.4 to 15.1 wether it would a upgrade license or i can download it or how does it go.Please help
