Upgrading Flash on Cisco 1941

[BHconsultants88]

Hi all

Just wondered if someone could give me advice on the best image file to use on a Cisco 1941. Currently, it is flashed with:

System image file is "flash0:c1900-universalk9_npe-mz.SPA.155-3.M3.bin"

The reason for the upgrade is my NAT is not working properly so just want to make sure it's not the image. Which version should I upgrade to?

Thanks in advance.

[marce1000]

  Follow the advice at cisco.com (support -> downloads) & choose your product type; then download the latest gold-starred release.

M.