Thanks, unfortunately there are likely to still be a lot of your unsupported phones in use, just like Windows XP was when wannacry broke. No doubt we'll see more IoT-type issues like this as time goes on.
Do you have snug information on whether this affects older, possibly out of support, IP phones such as the CP-7940G, CP-7942G, CP-7911G, CP-7970G and CP-7975G?