Everyone,
I have been able to extend the Wakaama example to build for lwIP sock IPv4 and IPv6 [1]. This extension builds on the great recent work by @gchorcht, @wosym, and others to enable IPv4 for lwIP.
I decided to just post a notice rather than create a WIP PR. I had to #ifdef-out code related to netif functions, so an implementation for lwIP, as @miri64 has started with #9343, would be useful first. Also, I'm not sure how extensively we want to start bringing in IPv4 for examples. I had to add several #ifdefs for things like `ipvN_addr_equal()`.
At any rate, the example should provide some food for thought on the issues around supporting both IP versions. It's also valuable to me to demo RIOT running LwM2M on IPv4!
Ken
[1] https://github.com/kb2ma/RIOT/tree/wakaama/lwip_ipv4_poc