Before upgrading, verify your router has sufficient DRAM and Flash memory by using the show version command. Typical Upgrade Steps
Cisco Modeling Labs (CML) / VIRL includes official images. You can convert the .bin to a .qcow2 format using the c1900-universalk9-mz.spa.157-3.m9.bin via the virl2 tools for better performance. C1900-universalk9-mz.spa.157-3.m9.bin Download
: Upgrading to a new release often requires more memory. You should verify your current resources using the show version command and compare them against the requirements in the Cisco IOS Upgrade Planner ROMMON Version Before upgrading, verify your router has sufficient DRAM