Found my answer, use correct version of doc:

https://kamailio.org/docs/modules/5.2.x/modules/ims_usrloc_pcscf.html#idm1042831636

From: sr-users <sr-users-bounces@lists.kamailio.org> On Behalf Of Martin W Woscek
Sent: Wednesday, June 17, 2020 8:47 AM
To: Kamailio (SER) - Users Mailing List <sr-users@lists.kamailio.org>
Subject: [SR-Users] kamailio 5.2.2 enabling hashing_type

Hello,

I’m revisiting some initial issues I had with P-CSCF.  I could not set the hashing type in my PCSCF (kamalio 5.2.2) so I simply commented it out and moved on. 

But now, I may need it as the P-CSCF is not handling INVITES coming from I-CSCF that originated  from external SIP server, where the endpoint (UE) is registered to the IMS but the P-CSCF sends the INVITE back to the S rather that the registered UE and fails.

kamailio.cfg:

modparam("ims_usrloc_pcscf", "hashing_type", 1)

So with that, when I set the hashing_type to 1,1 or 2 I get the following starting the pcscf:

Starting the P-CSCF:

Jun 17 08:25:30 ubuntu kamailio_pcscf[5753]:  * Not starting Kamailio IMS P-CSCF: invalid configuration file!
Jun 17 08:25:30 ubuntu kamailio_pcscf[5753]:  *
Jun 17 08:25:30 ubuntu kamailio_pcscf[5753]:  *  0(5766) ERROR: <core> [core/modparam.c:140]: set_mod_param_regex(): parameter <hashing_type> of type <2> not found in module <ims_usrloc_pcscf>
Jun 17 08:25:30 ubuntu kamailio_pcscf[5753]:  0(5766) CRITICAL: <core> [core/cfg.y:3510]: yyerror_at(): parse error in config file /etc/kamailio/pcscf/kamailio.cfg, line 364, column 47: Can't set module parameter

Am I missing some module that I did not include at compile time?  According to the docs, it has no additional dependencies other than the ims_usrloc_pcscf.so

https://kamailio.org/docs/modules/5.0.x/modules/ims_usrloc_pcscf.html#idp35204148

Any help is appreciated.

Thanks,

_Martin