Jon Shallow

libcoap LwIP support has been re-written in PR https://github.com/obgm/libcoap/pull/884, and so this should no longer be an issue.

Hmm. Given that observers are only associated with servers, and coap_session_release() only calls coap_session_free() if the session is a client I am not sure that there actually is an issue...

Actually, if Call-Home is implemented (aka RFC8071), where (D)TLS is set up in the opposite direction to CoAP, then it is possible that the Observer Subscription is in the (D)TLS...

Likely to be superseded by #926.

coap_run_once() (now known as coap_process_io()) will process everything it can before returning. > Is there a way to determine if any work has been done? (i.e. if any packets have...

There currently is no option to configure this. In `src/coap_openssl.c`, change all 3 occurrences of `TLS1_VERSION` to `TLS1_3_VERSION `for the `SSL_CTX_set_min_proto_version()` calls and rebuild the libcoap library. Note that DTLS1.3...

As the supprt becomes available in OpenSSL, GnuTLS, Mbed TLS and TinyDTLS libraries, there may need to be some minor changes to the `src/coap_{openssl|gnutls|mbedtls|tinydtls}.c` files to get it functioning correctly....

It is the version in the CLientHello that matters, not the version in the Record Layer Are you using PSK or PKI? - for PSK, if Identity Hint Callback is...

Yes, you need a minimum of opensssl 1.1.1 for TLS1.3. Until DTLS1.3 is supported by the TLS libraries that libcoap uses, then DTLS1.3 is not available in libcoap as the...

I would say that it is likely you are compiling against openssl-1.1.1, but linking against openssl-1.1.0 What does `ldd ../.libs/libcoap-3-openssl.so` tell you for the `libssl `and `libcrypto `libraries?