How to enable 100rel in asterisk

Asterisk Asterisk Support
1

Dear,

I could would like to how to get this config in sip.conf>>
SIP Options : 100rel early-session timer

I search from internet that it should add>>
Prack=yes?

But seems no working.

Thanks.

2

Hi,

Have the same issue, can Asterisk 13 add 100rel required header to 18X response ?