I have a Cisco SPA942 phone, which is no longer supported by Cisco. It's running the latest firmware available for this phone: 6.1.5(a). Cisco replaced the SPA942 with the SPA504G, which is almost identical to the SPA942 hardware-wise. I noticed that the SPA504G has a newer firmware available (7.4.6) that adds some features that I'd like to have (a call ignore soft button and G.722 HD support).
I tried downloading and executing the 7.4.6 firmware upgrade tool, and going through the screens it didn't tell me I couldn't apply this SPA504G update to the SPA942. I stopped short of clicking the Upgrade button on the final screen before the upgrade, as I wasn't sure if this upgrade would brick the phone.
Is it safe to apply this SPA504G update to the SPA942?