@grumvalski: have you checked if also makes sense to set the flag suggested by @bjokax CURLOPT_SSL_ENABLE_ALPN ?
* https://curl.se/libcurl/c/CURLOPT_SSL_ENABLE_ALPN.html
Wondering if there is any benefit of allowing protocol negotiation in Kamailio case.
Moreover, maybe we have to set it to http_client module - @oej: any opinion on http_client module?