On Tue, Feb 11, 2020 at 08:03:29AM +0900, mayamatakeshi wrote:
> Actually, my idea was to do something like this before handing the REGISTER
> to registrar save() function:
>                         remove_hf("Expires");
>                         append_hf("Expires: 200\r\n");
> However, this didn't work (or at least, it doesn't work with kamailio 4.3.7
> which is the one I use).

These changes aren't applied to the processing of the current message
until you call msg_apply_changes().

Try adding and see if it works.

        append_hf("Expires: 200\r\n");
        msg_apply_changes();