[root@f24-master ~]# ipa -vv -e xmlrpc_uri=https://id.vda.li/ipa/xml config-show
ipa: INFO: trying https://id.vda.li/ipa/json
ipa: INFO: Request: {
    "id": 0, 
    "method": "ping", 
    "params": [
        [], 
        {}
    ]
}
ipa: INFO: Response: {
    "error": null, 
    "id": 0, 
    "principal": "admin@VDA.LI", 
    "result": {
        "messages": [
            {
                "code": 13001, 
                "message": "API Version number was not sent, forward compatibility not guaranteed. Assuming server's API version, 2.156", 
                "name": "VersionMissing", 
                "type": "warning"
            }
        ], 
        "summary": "IPA server version 4.2.3. API version 2.156"
    }, 
    "version": "4.2.3"
}
ipa: INFO: Forwarding 'config_show/1' to json server 'https://id.vda.li/ipa/json'
ipa: INFO: Request: {
    "id": 0, 
    "method": "config_show/1", 
    "params": [
        [], 
        {
            "version": "2.210"
        }
    ]
}
ipa: INFO: Response: {
    "error": {
        "code": 905, 
        "message": "unknown command 'config_show/1'", 
        "name": "CommandError"
    }, 
    "id": 0, 
    "principal": "admin@VDA.LI", 
    "result": null, 
    "version": "4.2.3"
}
ipa: ERROR: unknown command 'config_show/1'

Same happens for every other command so I cannot even test the behavior.
It works against the same server as the thin client is.

[root@f24-master ~]# ipa -vv config-show
ipa: INFO: trying https://f24-master.ipa.ad.test/ipa/json
ipa: INFO: Forwarding 'config_show/1' to json server 'https://f24-master.ipa.ad.test/ipa/json'
ipa: INFO: Request: {
    "id": 0, 
    "method": "config_show/1", 
    "params": [
        [], 
        {
            "version": "2.210"
        }
    ]
}
ipa: INFO: Response: {
    "error": null, 
    "id": 0, 
    "principal": "admin@IPA.AD.TEST", 
    "result": {
        "result": {
            "ca_renewal_master_server": "f24-master.ipa.ad.test", 
            "ca_server_server": [
                "f24-master.ipa.ad.test"
            ], 
            "dn": "cn=ipaConfig,cn=etc,dc=ipa,dc=ad,dc=test", 
            "ipa_master_server": [
                "f24-master.ipa.ad.test"
            ], 
            "ipacertificatesubjectbase": [
                "O=IPA.AD.TEST"
            ], 
            "ipaconfigstring": [
                "AllowNThash"
            ], 
            "ipadefaultemaildomain": [
                "ipa.ad.test"
            ], 
            "ipadefaultloginshell": [
                "/bin/sh"
            ], 
            "ipadefaultprimarygroup": [
                "ipausers"
            ], 
            "ipagroupsearchfields": [
                "cn,description"
            ], 
            "ipahomesrootdir": [
                "/home"
            ], 
            "ipakrbauthzdata": [
                "nfs:NONE", 
                "MS-PAC"
            ], 
            "ipamaxusernamelength": [
                "32"
            ], 
            "ipamigrationenabled": [
                "FALSE"
            ], 
            "ipapwdexpadvnotify": [
                "4"
            ], 
            "ipasearchrecordslimit": [
                "100"
            ], 
            "ipasearchtimelimit": [
                "2"
            ], 
            "ipaselinuxusermapdefault": [
                "unconfined_u:s0-s0:c0.c1023"
            ], 
            "ipaselinuxusermaporder": [
                "guest_u:s0$xguest_u:s0$user_u:s0$staff_u:s0-s0:c0.c1023$unconfined_u:s0-s0:c0.c1023"
            ], 
            "ipausersearchfields": [
                "uid,givenname,sn,telephonenumber,ou,title"
            ], 
            "ntp_server_server": [
                "f24-master.ipa.ad.test"
            ]
        }, 
        "summary": null, 
        "value": null
    }, 
    "version": "4.4.0.201607151226GIT37bfd1f"
}
  Maximum username length: 32
  Home directory base: /home
  Default shell: /bin/sh
  Default users group: ipausers
  Default e-mail domain: ipa.ad.test
  Search time limit: 2
  Search size limit: 100
  User search fields: uid,givenname,sn,telephonenumber,ou,title
  Group search fields: cn,description
  Enable migration mode: FALSE
  Certificate Subject base: O=IPA.AD.TEST
  Password Expiration Notification (days): 4
  Password plugin features: AllowNThash
  SELinux user map order: guest_u:s0$xguest_u:s0$user_u:s0$staff_u:s0-s0:c0.c1023$unconfined_u:s0-s0:c0.c1023
  Default SELinux user: unconfined_u:s0-s0:c0.c1023
  Default PAC types: nfs:NONE, MS-PAC
  IPA masters: f24-master.ipa.ad.test
  IPA CA servers: f24-master.ipa.ad.test
  IPA NTP servers: f24-master.ipa.ad.test
  IPA CA renewal master: f24-master.ipa.ad.test