diff --git a/.github/workflows/composite/unit-integration-test-runner/run-integration-tests.sh b/.github/workflows/composite/unit-integration-test-runner/run-integration-tests.sh
index a89779a3..b0f8fac8 100755
--- a/.github/workflows/composite/unit-integration-test-runner/run-integration-tests.sh
+++ b/.github/workflows/composite/unit-integration-test-runner/run-integration-tests.sh
@@ -1,4 +1,5 @@
 #!/bin/bash
+set -e
 
 INFO_BG="\033[0m\033[48;2;5;49;70m"
 INFO_FG="\033[38;2;19;181;255m"
diff --git a/.github/workflows/composite/unit-integration-test-runner/run-unit-tests.sh b/.github/workflows/composite/unit-integration-test-runner/run-unit-tests.sh
index 0da15bf5..88027bb1 100755
--- a/.github/workflows/composite/unit-integration-test-runner/run-unit-tests.sh
+++ b/.github/workflows/composite/unit-integration-test-runner/run-unit-tests.sh
@@ -1,4 +1,10 @@
 #!/bin/bash
+set -e
+
+if [ -d "/usr/lib/x86_64-linux-gnu/" ]; then
+export LD_LIBRARY_PATH=/usr/lib/x86_64-linux-gnu:$LD_LIBRARY_PATH
+fi
+
 
 echo "::group::Run unit tests ('$1' $CC / $CXX)"
 cd "$GITHUB_WORKSPACE/core"
diff --git a/.github/workflows/composite/unit-test-framework/action.yaml b/.github/workflows/composite/unit-test-framework/action.yaml
index e0114ddc..70b3fd18 100644
--- a/.github/workflows/composite/unit-test-framework/action.yaml
+++ b/.github/workflows/composite/unit-test-framework/action.yaml
@@ -18,7 +18,7 @@ runs:
   steps:
     - name: Build and Cache Unit Test framework ('${{ inputs.os }}' ${{ inputs.compilers }})
       id: unit-test-framework
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: |
           cgreen
@@ -27,7 +27,7 @@ runs:
           ${{ inputs.os }}-cgreen-${{ inputs.version }}-
     - name: Checkout Unit Test framework
       if: steps.unit-test-framework.outputs.cache-hit != 'true'
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: cgreen-devs/cgreen
         ref: ${{ matrix.cgreen }}
diff --git a/.github/workflows/run-tests.yml b/.github/workflows/run-tests.yml
index 66fe81d8..0c70fab6 100644
--- a/.github/workflows/run-tests.yml
+++ b/.github/workflows/run-tests.yml
@@ -25,11 +25,11 @@ jobs:
 #            group: organization/macos-gh
     steps:
       - name: Checkout project
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           token: ${{ secrets.GH_TOKEN }}
       - name: Checkout actions
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: pubnub/client-engineering-deployment-tools
           ref: v1
diff --git a/.pubnub.yml b/.pubnub.yml
index 76c5b55c..343bfd48 100644
--- a/.pubnub.yml
+++ b/.pubnub.yml
@@ -1,8 +1,17 @@
 name: c-core
 schema: 1
-version: "4.14.1"
+version: "4.15.0"
 scm: github.com/pubnub/c-core
 changelog:
+  - date: 2024-11-25
+    version: v4.15.0
+    changes:
+      - type: feature
+        text: "Add custom message type support for the following APIs: publish, signal, share file, subscribe and history."
+      - type: feature
+        text: "Add `pubnub_set_ipv4_connectivity` and `pubnub_set_ipv6_connectivity` to `pubnub_coreapi` to switch preferred connectivity protocol."
+      - type: bug
+        text: "Make sure that in case of connection close (including because of error) proxy context object will be reset."
   - date: 2024-10-24
     version: v4.14.1
     changes:
@@ -875,7 +884,7 @@ sdks:
             distribution-type: source code
             distribution-repository: GitHub release
             package-name: C-Core
-            location: https://github.com/pubnub/c-core/releases/tag/v4.14.1
+            location: https://github.com/pubnub/c-core/releases/tag/v4.15.0
             requires:
               -
                 name: "miniz"
@@ -941,7 +950,7 @@ sdks:
             distribution-type: source code
             distribution-repository: GitHub release
             package-name: C-Core
-            location: https://github.com/pubnub/c-core/releases/tag/v4.14.1
+            location: https://github.com/pubnub/c-core/releases/tag/v4.15.0
             requires:
               -
                 name: "miniz"
@@ -1007,7 +1016,7 @@ sdks:
             distribution-type: source code
             distribution-repository: GitHub release
             package-name: C-Core
-            location: https://github.com/pubnub/c-core/releases/tag/v4.14.1
+            location: https://github.com/pubnub/c-core/releases/tag/v4.15.0
             requires:
               -
                 name: "miniz"
@@ -1069,7 +1078,7 @@ sdks:
             distribution-type: source code
             distribution-repository: GitHub release
             package-name: C-Core
-            location: https://github.com/pubnub/c-core/releases/tag/v4.14.1
+            location: https://github.com/pubnub/c-core/releases/tag/v4.15.0
             requires:
               -
                 name: "miniz"
@@ -1130,7 +1139,7 @@ sdks:
             distribution-type: source code
             distribution-repository: GitHub release
             package-name: C-Core
-            location: https://github.com/pubnub/c-core/releases/tag/v4.14.1
+            location: https://github.com/pubnub/c-core/releases/tag/v4.15.0
             requires:
               -
                 name: "miniz"
@@ -1186,7 +1195,7 @@ sdks:
             distribution-type: source code
             distribution-repository: GitHub release
             package-name: C-Core
-            location: https://github.com/pubnub/c-core/releases/tag/v4.14.1
+            location: https://github.com/pubnub/c-core/releases/tag/v4.15.0
             requires:
               -
                 name: "miniz"
@@ -1239,7 +1248,7 @@ sdks:
             distribution-type: source code
             distribution-repository: GitHub release
             package-name: C-Core
-            location: https://github.com/pubnub/c-core/releases/tag/v4.14.1
+            location: https://github.com/pubnub/c-core/releases/tag/v4.15.0
             requires:
               -
                 name: "miniz"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index a266a427..2d05815a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,13 @@
+## v4.15.0
+November 25 2024
+
+#### Added
+- Add custom message type support for the following APIs: publish, signal, share file, subscribe and history.
+- Add `pubnub_set_ipv4_connectivity` and `pubnub_set_ipv6_connectivity` to `pubnub_coreapi` to switch preferred connectivity protocol.
+
+#### Fixed
+- Make sure that in case of connection close (including because of error) proxy context object will be reset.
+
 ## v4.14.1
 October 24 2024
 
diff --git a/Dockerfile b/Dockerfile
index 3364296f..125ccbf5 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -37,11 +37,11 @@ RUN apt-get install -y cmake g++ ruby ruby-dev git ninja-build libboost-all-dev
 RUN git clone https://github.com/cgreen-devs/cgreen.git
 RUN cd cgreen && git checkout 1.4.1 && make
 
-FROM ubuntu:20.04 
+FROM ubuntu:20.04
 ARG DEBIAN_FRONTEND=noninteractive
 WORKDIR /home
 
-ENV GMOCK_VER=1.7.0 
+ENV GMOCK_VER=1.7.0
 ENV CMAKE_CXX_COMPILER=/usr/bin/g++
 
 RUN apt-get update
@@ -83,7 +83,7 @@ RUN if [ -z "$MOCK_SERVER_DOCKER" ]; then \
         -Icucumber-cpp/include -Icucumber-cpp/build/src/ -Iposix -Icore -I. -Icpp \
         -D PUBNUB_CRYPTO_API=1 -D PUBNUB_USE_SSL=0 -D MOCK_SERVER_DOCKER; \
     fi
-    
+
 
 RUN g++ -o steps BoostSteps.o cpp/pubnub_sync.a cucumber-cpp/build/src/libcucumber-cpp.a \
         -Lboost -lboost_unit_test_framework -lpthread -lboost_regex \
diff --git a/core/Makefile b/core/Makefile
index 79de3513..3727ea07 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -66,7 +66,7 @@ pubnub_timer_list_unittest: pubnub_timer_list.c pubnub_timer_list_unit_test.c
 	#$(GCOVR) -r . --html --html-details -o coverage.html
 
 
-PROXY_PROJECT_SOURCEFILES = pubnub_proxy_core.c pubnub_proxy.c pbhttp_digest.c pbntlm_core.c pbntlm_packer_std.c pubnub_generate_uuid_v4_random_std.c ../lib/pubnub_parse_ipv4_addr.c ../lib/pubnub_parse_ipv6_addr.c  ../lib/md5/md5.c
+PROXY_PROJECT_SOURCEFILES = pubnub_proxy_core.c pubnub_proxy.c pbhttp_digest.c pbntlm_core.c pbntlm_packer_std.c pubnub_generate_uuid_v4_random_std.c pubnub_dns_servers.c ../lib/pubnub_parse_ipv4_addr.c ../lib/pubnub_parse_ipv6_addr.c  ../lib/md5/md5.c
 
 pubnub_proxy_unittest: $(PROJECT_SOURCEFILES) $(PROXY_PROJECT_SOURCEFILES) pubnub_proxy_unit_test.c
 	gcc -o pubnub_proxy_unit_test.so -shared $(CFLAGS) $(LDFLAGS) -D PUBNUB_CALLBACK_API -D PUBNUB_PROXY_API=1 -Wall $(COVERAGE_FLAGS) -fPIC $(PROJECT_SOURCEFILES) $(PROXY_PROJECT_SOURCEFILES) pubnub_proxy_unit_test.c -lcgreen -lm
@@ -87,17 +87,47 @@ CRYPTO_INCLUDES += -I ../openssl/.
 CRYPTO_LIBS += -lssl -lcrypto
 CRYPTO_SOURCEFILES += pubnub_crypto.c pbcc_crypto.c pbcc_crypto_aes_cbc.c pbcc_crypto_legacy.c ../openssl/pbaes256.c
 
+
+OS := $(shell uname)
+ifeq ($(OS),Darwin)
+	# Ensure OpenSSL paths are set.
+	OPENSSL_CFLAGS := $(shell pkg-config --cflags openssl 2>/dev/null)
+	OPENSSL_LIBS := $(shell pkg-config --libs openssl 2>/dev/null)
+	ifneq ($(OPENSSL_CFLAGS),)
+		CRYPTO_INCLUDES += $(OPENSSL_CFLAGS)
+	endif
+	ifneq ($(OPENSSL_LIBS),)
+		CRYPTO_LIBS += $(OPENSSL_LIBS)
+	endif
+else
+	ifeq ($(shell test -d "/usr/local/opt/openssl" && echo yes || echo no),yes)
+		CRYPTO_INCLUDES += -I/usr/local/opt/openssl/include
+	else
+		# Path on GitHub Action Runner (ubuntu-latest image)
+		ifeq ($(shell test -d "/usr/include/openssl" && echo yes || echo no),yes)
+			CRYPTO_INCLUDES += -I/usr/include
+		endif
+	endif
+	# Path on GitHub Action Runner (ubuntu-latest image)
+	ifeq ($(shell test -d "/usr/lib/x86_64-linux-gnu" && echo yes || echo no),yes)
+		CRYPTO_LIBS += -L/usr/lib/x86_64-linux-gnu -Wl,-Bdynamic
+	endif
+endif
+
+
 pbcc_crypto_unittest: $(PROJECT_SOURCEFILES) $(CRYPTO_SOURCEFILES) pbcc_crypto_unit_tests.c
-	gcc -o pbcc_crypto_unit_test.so -shared $(CFLAGS) $(LDFLAGS) $(CRYPTO_INCLUDES) $(CRYPTO_LIBS) -D PUBNUB_CRYPTO_API=1 -Wall $(COVERAGE_FLAGS) -fPIC $(PROJECT_SOURCEFILES) $(CRYPTO_SOURCEFILES) test/pubnub_test_mocks.c pbcc_crypto_unit_tests.c -lcgreen -lm
+	gcc -o pbcc_crypto_unit_test.so -shared $(CFLAGS) $(LDFLAGS) $(CRYPTO_INCLUDES) -D PUBNUB_CRYPTO_API=1 -Wall $(COVERAGE_FLAGS) -fPIC $(PROJECT_SOURCEFILES) $(CRYPTO_SOURCEFILES) test/pubnub_test_mocks.c pbcc_crypto_unit_tests.c $(CRYPTO_LIBS) -lcgreen -lm
 #	gcc -o pubnub_core_unit_testo  $(CFLAGS) -Wall $(COVERAGE_FLAGS) $(PROJECT_SOURCEFILES) pbcc_crypto_unit_tests.c -lcgreen -lm
+	#ldd pbcc_crypto_unit_test.so
 	$(CGREEN_RUNNER) ./pbcc_crypto_unit_test.so
 	#$(GCOVR) -r . --html --html-details -o coverage.html
 
 SUBSCRIBE_V2_SOURCEFILES += pubnub_subscribe_v2.c pbcc_subscribe_v2.c 
 
 pubnub_crypto_unittest: $(PROJECT_SOURCEFILES) $(CRYPTO_SOURCEFILES) $(SUBSCRIBE_V2_SOURCEFILES) pubnub_crypto_unit_tests.c
-	gcc -o pubnub_crypto_unit_test.so -shared $(CFLAGS) $(LDFLAGS) $(CRYPTO_INCLUDES) $(CRYPTO_LIBS) -D PUBNUB_CRYPTO_API=1 -D PUBNUB_USE_SUBSCRIBE_V2=1 -Wall $(COVERAGE_FLAGS) -fPIC $(PROJECT_SOURCEFILES) $(CRYPTO_SOURCEFILES) $(SUBSCRIBE_V2_SOURCEFILES) test/pubnub_test_mocks.c pubnub_crypto_unit_tests.c -lcgreen -lm
+	gcc -o pubnub_crypto_unit_test.so -shared $(CFLAGS) $(LDFLAGS) $(CRYPTO_INCLUDES) -D PUBNUB_CRYPTO_API=1 -D PUBNUB_USE_SUBSCRIBE_V2=1 -Wall $(COVERAGE_FLAGS) -fPIC $(PROJECT_SOURCEFILES) $(CRYPTO_SOURCEFILES) $(SUBSCRIBE_V2_SOURCEFILES) test/pubnub_test_mocks.c pubnub_crypto_unit_tests.c $(CRYPTO_LIBS) -lcgreen -lm
 #	gcc -o pubnub_core_unit_testo  $(CFLAGS) -Wall $(COVERAGE_FLAGS) $(PROJECT_SOURCEFILES) pubnub_crypto_unit_tests.c -lcgreen -lm
+	#ldd pubnub_crypto_unit_test.so
 	$(CGREEN_RUNNER) ./pubnub_crypto_unit_test.so
 
 
diff --git a/core/pbcc_fetch_history.c b/core/pbcc_fetch_history.c
index 24b45a65..20d417d6 100644
--- a/core/pbcc_fetch_history.c
+++ b/core/pbcc_fetch_history.c
@@ -21,6 +21,7 @@ enum pubnub_res pbcc_fetch_history_prep(struct pbcc_context* pb,
                                   const char*          channel,
                                   unsigned int         max_per_channel,
                                   enum pubnub_tribool  include_meta,
+                                  enum pubnub_tribool  include_custom_message_type,
                                   enum pubnub_tribool  include_message_type,
                                   enum pubnub_tribool  include_user_id,
                                   enum pubnub_tribool  include_message_actions,
@@ -59,7 +60,8 @@ enum pubnub_res pbcc_fetch_history_prep(struct pbcc_context* pb,
     if (max_per_channel) { ADD_URL_PARAM(qparam, max, max_per_ch_cnt_buf); }
 
     if (include_meta != pbccNotSet) { ADD_URL_PARAM(qparam, include_meta, include_meta == pbccTrue ? "true" : "false"); }
-    if (include_message_type != pbccNotSet) { ADD_URL_PARAM(qparam, include_message_type, include_meta == pbccTrue ? "true" : "false"); }
+    if (include_custom_message_type != pbccNotSet) { ADD_URL_PARAM(qparam, include_custom_message_type, include_custom_message_type == pbccTrue ? "true" : "false"); }
+    if (include_message_type != pbccNotSet) { ADD_URL_PARAM(qparam, include_message_type, include_message_type == pbccTrue ? "true" : "false"); }
     if (include_user_id != pbccNotSet) { ADD_URL_PARAM(qparam, include_uuid, include_user_id == pbccTrue ? "true" : "false"); }
 #if PUBNUB_CRYPTO_API
     if (pb->secret_key == NULL) { ADD_URL_AUTH_PARAM(pb, qparam, auth); }
diff --git a/core/pbcc_fetch_history.h b/core/pbcc_fetch_history.h
index c16739e4..d2072e77 100644
--- a/core/pbcc_fetch_history.h
+++ b/core/pbcc_fetch_history.h
@@ -10,6 +10,7 @@ enum pubnub_res pbcc_fetch_history_prep(struct pbcc_context* pb,
                                   const char*          channel,
                                   unsigned int         max_per_channel,
                                   enum pubnub_tribool  include_meta,
+                                  enum pubnub_tribool  include_custom_message_type,
                                   enum pubnub_tribool  include_message_type,
                                   enum pubnub_tribool  include_user_id,
                                   enum pubnub_tribool  include_message_actions,
diff --git a/core/pbcc_subscribe_v2.c b/core/pbcc_subscribe_v2.c
index e1c50650..4ed2e13c 100644
--- a/core/pbcc_subscribe_v2.c
+++ b/core/pbcc_subscribe_v2.c
@@ -27,7 +27,7 @@
 enum pubnub_res pbcc_subscribe_v2_prep(struct pbcc_context* p,
                                        char const*          channel,
                                        char const*          channel_group,
-                                       unsigned*            heartbeat,
+                                       const unsigned*      heartbeat,
                                        char const*          filter_expr)
 {
     char        region_str[20];
@@ -254,6 +254,9 @@ struct pubnub_v2_message pbcc_get_msg_v2(struct pbcc_context* p)
                     found.end - found.start,
                     &rslt.payload.size
             );
+        } else {
+            rslt.payload.ptr  = (char*)found.start;
+            rslt.payload.size = found.end - found.start;
         }
 #else
         rslt.payload.ptr  = (char*)found.start;
@@ -303,6 +306,11 @@ struct pubnub_v2_message pbcc_get_msg_v2(struct pbcc_context* p)
         rslt.message_type = pbsbPublished;
     }
 
+    if (jonmpOK == pbjson_get_object_value(&el, "cmt", &found)) {
+        rslt.custom_message_type.ptr  = (char*)found.start + 1;
+        rslt.custom_message_type.size = found.end - found.start - 2;
+    }
+
     jpresult = pbjson_get_object_value(&el, "p", &found);
     if (jonmpOK == jpresult) {
         struct pbjson_elem titel;
diff --git a/core/pbcc_subscribe_v2.h b/core/pbcc_subscribe_v2.h
index 642f969a..cce9c340 100644
--- a/core/pbcc_subscribe_v2.h
+++ b/core/pbcc_subscribe_v2.h
@@ -15,7 +15,7 @@ struct pbcc_context;
 enum pubnub_res pbcc_subscribe_v2_prep(struct pbcc_context* p,
                                        char const*          channel,
                                        char const*          channel_group,
-                                       unsigned*            heartbeat,
+                                       const unsigned*      heartbeat,
                                        char const*          filter_expr);
 
 
diff --git a/core/pubnub_ccore_pubsub.c b/core/pubnub_ccore_pubsub.c
index 6822467e..db886ce9 100644
--- a/core/pubnub_ccore_pubsub.c
+++ b/core/pubnub_ccore_pubsub.c
@@ -525,6 +525,7 @@ enum pubnub_res pbcc_append_url_param_encoded(struct pbcc_context* pb,
 enum pubnub_res pbcc_publish_prep(struct pbcc_context* pb,
                                   const char*          channel,
                                   const char*          message,
+                                  const char*          custom_message_type,
                                   bool                 store_in_history,
                                   bool                 norep,
                                   char const*          meta,
@@ -596,7 +597,7 @@ enum pubnub_res pbcc_publish_prep(struct pbcc_context* pb,
     URL_PARAMS_INIT(qparam, PUBNUB_MAX_URL_PARAMS);
     if (uname) { ADD_URL_PARAM(qparam, pnsdk, uname); }
     ADD_URL_PARAM(qparam, uuid, user_id);
-    if (ttl != SIZE_MAX) { ADD_URL_PARAM_SIZET(qparam, ttl, ttl); }
+    if (ttl != 0 && ttl != SIZE_MAX) { ADD_URL_PARAM_SIZET(qparam, ttl, ttl); }
 #if PUBNUB_CRYPTO_API
     if (pb->secret_key == NULL) { ADD_URL_AUTH_PARAM(pb, qparam, auth); }
     ADD_TS_TO_URL_PARAM();
@@ -606,6 +607,9 @@ enum pubnub_res pbcc_publish_prep(struct pbcc_context* pb,
     if (!store_in_history) { ADD_URL_PARAM(qparam, store, "0"); }
     if (norep) { ADD_URL_PARAM(qparam, norep, "true"); }
     if (meta) { ADD_URL_PARAM(qparam, meta, meta); }
+    if (custom_message_type) {
+        ADD_URL_PARAM(qparam, custom_message_type, custom_message_type);
+    }
 
 #if PUBNUB_CRYPTO_API
     SORT_URL_PARAMETERS(qparam);
@@ -667,7 +671,8 @@ enum pubnub_res pbcc_sign_url(struct pbcc_context* pc, const char* msg, enum pub
 
 enum pubnub_res pbcc_signal_prep(struct pbcc_context* pb,
                                  const char* channel,
-                                 const char* message)
+                                 const char* message,
+                                 const char* custom_message_type)
 {
     enum pubnub_res   rslt = PNR_OK;
     char const* const uname = pubnub_uname();
@@ -689,6 +694,9 @@ enum pubnub_res pbcc_signal_prep(struct pbcc_context* pb,
     URL_PARAMS_INIT(qparam, PUBNUB_MAX_URL_PARAMS);
     if (uname) { ADD_URL_PARAM(qparam, pnsdk, uname); }
     if (user_id) { ADD_URL_PARAM(qparam, uuid, user_id); }
+    if (custom_message_type) {
+        ADD_URL_PARAM(qparam, custom_message_type, custom_message_type);
+    }
 #if PUBNUB_CRYPTO_API
     if (pb->secret_key == NULL) { ADD_URL_AUTH_PARAM(pb, qparam, auth); }
     ADD_TS_TO_URL_PARAM();
@@ -716,7 +724,7 @@ enum pubnub_res pbcc_signal_prep(struct pbcc_context* pb,
 enum pubnub_res pbcc_subscribe_prep(struct pbcc_context* p,
                                     char const*          channel,
                                     char const*          channel_group,
-                                    unsigned*            heartbeat)
+                                    const unsigned*      heartbeat)
 {
     char const* user_id = pbcc_user_id_get(p);
     char const* const uname = pubnub_uname();
diff --git a/core/pubnub_ccore_pubsub.h b/core/pubnub_ccore_pubsub.h
index 1e03e6a8..737cbfed 100644
--- a/core/pubnub_ccore_pubsub.h
+++ b/core/pubnub_ccore_pubsub.h
@@ -477,6 +477,7 @@ void pbcc_via_post_headers(struct pbcc_context* p, char* header, size_t max_leng
 enum pubnub_res pbcc_publish_prep(struct pbcc_context* pb,
                                   const char*          channel,
                                   const char*          message,
+                                  const char*          custom_message_type,
                                   bool                 store_in_history,
                                   bool                 norep,
                                   char const*          meta,
@@ -488,7 +489,8 @@ enum pubnub_res pbcc_publish_prep(struct pbcc_context* pb,
  */
 enum pubnub_res pbcc_signal_prep(struct pbcc_context* pb,
                                  const char* channel,
-                                 const char* message);
+                                 const char* message,
+                                 const char* custom_message_type);
 
 /** Prepares the Subscribe operation (transaction), mostly by
     formatting the URI of the HTTP request.
@@ -496,7 +498,7 @@ enum pubnub_res pbcc_signal_prep(struct pbcc_context* pb,
 enum pubnub_res pbcc_subscribe_prep(struct pbcc_context* p,
                                     char const*          channel,
                                     char const*          channel_group,
-                                    unsigned*            heartbeat);
+                                    const unsigned*            heartbeat);
 
 
 /** Split @p buf string containing a JSON array (with arbitrary
diff --git a/core/pubnub_coreapi.c b/core/pubnub_coreapi.c
index 5eec3c42..da82efdb 100644
--- a/core/pubnub_coreapi.c
+++ b/core/pubnub_coreapi.c
@@ -471,3 +471,20 @@ int pubnub_last_http_response_body(pubnub_t* pb, pubnub_chamebl_t* o_msg)
     pubnub_mutex_unlock(pb->monitor);
     return 0;
 }
+
+#if PUBNUB_USE_IPV6
+void pubnub_set_ipv4_connectivity(pubnub_t *p)
+{
+    pubnub_mutex_lock(p->monitor);
+    p->options.ipv6_connectivity = false;
+    pubnub_mutex_unlock(p->monitor);
+}
+
+void pubnub_set_ipv6_connectivity(pubnub_t *p)
+{
+    pubnub_mutex_lock(p->monitor);
+    p->options.ipv6_connectivity = true;
+    pubnub_mutex_unlock(p->monitor);
+}
+#endif /* PUBNUB_USE_IPV6 */
+
diff --git a/core/pubnub_coreapi.h b/core/pubnub_coreapi.h
index e803c828..99656480 100644
--- a/core/pubnub_coreapi.h
+++ b/core/pubnub_coreapi.h
@@ -439,4 +439,14 @@ PUBNUB_EXTERN int pubnub_get_error_message(pubnub_t* pb, pubnub_chamebl_t* o_msg
  */
 PUBNUB_EXTERN int pubnub_last_http_response_body(pubnub_t* pb, pubnub_chamebl_t* o_msg);
 
+#if PUBNUB_USE_IPV6
+/** IPv4 connectivity type for @p.
+    Use IPv4 addresses to establish connection with remote origin. */
+PUBNUB_EXTERN void pubnub_set_ipv4_connectivity(pubnub_t *p);
+
+/** IPv6 connectivity type for @p.
+    Use IPv6 addresses to establish connection with remote origin. */
+PUBNUB_EXTERN void pubnub_set_ipv6_connectivity(pubnub_t *p);
+#endif
+
 #endif /* defined INC_PUBNUB_COREAPI */
diff --git a/core/pubnub_coreapi_ex.c b/core/pubnub_coreapi_ex.c
index 119a28c7..30fdfa66 100644
--- a/core/pubnub_coreapi_ex.c
+++ b/core/pubnub_coreapi_ex.c
@@ -27,12 +27,13 @@
 struct pubnub_publish_options pubnub_publish_defopts(void)
 {
     struct pubnub_publish_options result;
-    result.store      = true;
-    result.cipher_key = NULL;
-    result.replicate  = true;
-    result.meta       = NULL;
-    result.method     = pubnubSendViaGET;
-    result.ttl        = SIZE_MAX;
+    result.store               = true;
+    result.cipher_key          = NULL;
+    result.replicate           = true;
+    result.meta                = NULL;
+    result.method              = pubnubSendViaGET;
+    result.ttl                 = 0;
+    result.custom_message_type = NULL;
     return result;
 }
 
@@ -85,6 +86,7 @@ enum pubnub_res pubnub_publish_ex(pubnub_t*                     pb,
     rslt = pbcc_publish_prep(&pb->core,
                              channel,
                              message,
+                             opts.custom_message_type,
                              opts.store,
                              !opts.replicate,
                              opts.meta,
@@ -102,6 +104,40 @@ enum pubnub_res pubnub_publish_ex(pubnub_t*                     pb,
     return rslt;
 }
 
+struct pubnub_signal_options pubnub_signal_defopts(void)
+{
+    struct pubnub_signal_options result;
+    result.custom_message_type = NULL;
+    return result;
+}
+
+enum pubnub_res pubnub_signal_ex(
+    pubnub_t* pb,
+    const char* channel,
+    const char* message,
+    struct pubnub_signal_options opts)
+{
+    enum pubnub_res rslt;
+
+    PUBNUB_ASSERT(pb_valid_ctx_ptr(pb));
+
+    pubnub_mutex_lock(pb->monitor);
+    if (!pbnc_can_start_transaction(pb)) {
+        pubnub_mutex_unlock(pb->monitor);
+        return PNR_IN_PROGRESS;
+    }
+
+    rslt = pbcc_signal_prep(&pb->core, channel, message, opts.custom_message_type);
+    if (PNR_STARTED == rslt) {
+        pb->trans            = PBTT_SIGNAL;
+        pb->core.last_result = PNR_STARTED;
+        pbnc_fsm(pb);
+        rslt = pb->core.last_result;
+    }
+    pubnub_mutex_unlock(pb->monitor);
+
+    return rslt;
+}
 
 struct pubnub_subscribe_options pubnub_subscribe_defopts(void)
 {
diff --git a/core/pubnub_coreapi_ex.h b/core/pubnub_coreapi_ex.h
index 79a88b30..f48eec6a 100644
--- a/core/pubnub_coreapi_ex.h
+++ b/core/pubnub_coreapi_ex.h
@@ -65,11 +65,17 @@ struct pubnub_publish_options {
         API.
      */
     size_t ttl;
+    /** User-specified message type.
+        Important: String limited by **3**-**50** case-sensitive alphanumeric
+        characters with only `-` and `_` special characters allowed.
+     */
+    char const* custom_message_type;
 };
 
 /** This returns the default options for publish V1 transactions.
     Will set `store = true`, `cipher_key = NULL`, `replicate = true`,
-    `meta = NULL` and `method = pubnubPublishViaGet`
+    `meta = NULL`, `method = pubnubPublishViaGet`, `ttl=0`, and
+    `custom_message_type=NULL`.
  */
 PUBNUB_EXTERN struct pubnub_publish_options pubnub_publish_defopts(void);
 
@@ -85,7 +91,7 @@ PUBNUB_EXTERN struct pubnub_publish_options pubnub_publish_defopts(void);
     @param p The Pubnub context. Can't be NULL.
     @param channel The string with the channel name to publish to. Can't be
    NULL.
-    @param opt Publish V1 options
+    @param opts Publish V1 options
     @return #PNR_STARTED on success, an error otherwise
 */
 PUBNUB_EXTERN enum pubnub_res pubnub_publish_ex(pubnub_t*                     p,
@@ -94,6 +100,41 @@ PUBNUB_EXTERN enum pubnub_res pubnub_publish_ex(pubnub_t*                     p,
                                   struct pubnub_publish_options opts);
 
 
+/** Options for "extended" signal V1. */
+struct pubnub_signal_options {
+    /** User-specified message type.
+        Important: String limited by **3**-**50** case-sensitive alphanumeric
+        characters with only `-` and `_` special characters allowed.
+     */
+    char const* custom_message_type;
+};
+
+/** This returns the default options for signal V1 transactions.
+    Will set `custom_message_type=NULL`. */
+PUBNUB_EXTERN struct pubnub_signal_options pubnub_signal_defopts(void);
+
+/** The extended signal V1. Basically the same as pubnub_signal(),
+    but with added optional parameters in @p opts.
+
+    Basic usage:
+
+        struct pubnub_signal_options opt = pubnub_signal_defopts();
+        opt.custom_message_type = "test-message-type";
+        pbresult = pubnub_signal_ex(pn, "my_channel", "status:active", opt);
+
+    @param pb The pubnub context. Can't be NULL
+    @param channel The string with the channel to signal to.
+    @param message The signal message to send, expected to be in JSON format
+    @param opts Signal V1 options
+    @return #PNR_STARTED on success, an error otherwise
+*/
+PUBNUB_EXTERN enum pubnub_res pubnub_signal_ex(
+    pubnub_t* pb,
+    const char* channel,
+    const char* message,
+    struct pubnub_signal_options opts);
+
+
 /** Options for "extended" subscribe. */
 struct pubnub_subscribe_options {
     /** Channel group (a comma-delimited list of channel group names).
diff --git a/core/pubnub_dns_servers.c b/core/pubnub_dns_servers.c
index 5a8eb32c..57a63d33 100644
--- a/core/pubnub_dns_servers.c
+++ b/core/pubnub_dns_servers.c
@@ -33,7 +33,6 @@ void pubnub_dns_servers_deinit(void)
     pubnub_mutex_destroy(m_lock);
 }
 
-
 int pubnub_dns_set_primary_server_ipv4(struct pubnub_ipv4_address ipv4_address)
 {
     uint8_t* ipv4 = ipv4_address.ipv4;
diff --git a/core/pubnub_dns_servers.h b/core/pubnub_dns_servers.h
index 4a742990..2a77f411 100644
--- a/core/pubnub_dns_servers.h
+++ b/core/pubnub_dns_servers.h
@@ -2,6 +2,7 @@
 #if !defined INC_PUBNUB_DNS_SERVERS
 #define INC_PUBNUB_DNS_SERVERS
 
+#include "core/pubnub_api_types.h"
 #include <stdint.h>
 
 /** IPv4 Address, in binary format.
diff --git a/core/pubnub_fetch_history.c b/core/pubnub_fetch_history.c
index c4626190..85e729fa 100644
--- a/core/pubnub_fetch_history.c
+++ b/core/pubnub_fetch_history.c
@@ -23,6 +23,7 @@ struct pubnub_fetch_history_options pubnub_fetch_history_defopts(void)
     rslt.include_message_type = false;
     rslt.include_user_id = false;
     rslt.include_message_actions = false;
+    rslt.include_custom_message_type = false;
 
     return rslt;
 }
@@ -45,6 +46,7 @@ enum pubnub_res pubnub_fetch_history(pubnub_t*                     pb,
                              channel,
                              opt.max_per_channel,
                              opt.include_meta ? pbccTrue : pbccFalse,
+                             opt.include_custom_message_type ? pbccTrue : pbccFalse,
                              opt.include_message_type ? pbccTrue : pbccFalse,
                              opt.include_user_id ? pbccTrue : pbccFalse,
                              opt.include_message_actions ? pbccTrue : pbccFalse,
diff --git a/core/pubnub_fetch_history.h b/core/pubnub_fetch_history.h
index 45e92c42..2379a3d2 100644
--- a/core/pubnub_fetch_history.h
+++ b/core/pubnub_fetch_history.h
@@ -55,6 +55,10 @@ struct pubnub_fetch_history_options {
      * false.
      */
     bool include_message_actions;
+    /** Include messages' custom type flag.
+        Message / signal and file messages may contain user-provided type.
+     */
+    bool include_custom_message_type;
 };
 
 /** This returns the default options for fetch history transactions.
diff --git a/core/pubnub_internal_common.h b/core/pubnub_internal_common.h
index ba6a733e..f30cdc82 100644
--- a/core/pubnub_internal_common.h
+++ b/core/pubnub_internal_common.h
@@ -206,7 +206,7 @@ struct pubnub_options {
      */
     bool use_http_keep_alive : 1;
 
-#if PUBNUB_USE_IPV6 && defined(PUBNUB_CALLBACK_API)
+#if PUBNUB_USE_IPV6
     /* Connectivity type(true-Ipv6/false-Ipv4) chosen on a given context */
     bool ipv6_connectivity : 1;
 #endif
diff --git a/core/pubnub_netcore.c b/core/pubnub_netcore.c
index 62bad26b..227faabb 100644
--- a/core/pubnub_netcore.c
+++ b/core/pubnub_netcore.c
@@ -186,6 +186,10 @@ static bool should_keep_alive(struct pubnub_* pb, enum pubnub_res rslt)
 
 static void close_connection(struct pubnub_* pb)
 {
+#if PUBNUB_PROXY_API
+    pbproxy_handle_connection_close(pb);
+#endif /* PUBNUB_PROXY_API */
+
     if (pbpal_close(pb) <= 0) {
 #if PUBNUB_NEED_RETRY_AFTER_CLOSE
         PUBNUB_LOG_TRACE("close_connection(): pb->flags.retry_after_close=%d\n",
@@ -588,7 +592,7 @@ int pbnc_fsm(struct pubnub_* pb)
         if (0 == i) {
             goto next_state;
         }
-        else if (i < 0) {
+        if (i < 0) {
             pb->core.last_result = PNR_CONNECT_FAILED;
 #if PUBNUB_ADNS_RETRY_AFTER_CLOSE
             if (pb->flags.retry_after_close) {
diff --git a/core/pubnub_proxy_core.c b/core/pubnub_proxy_core.c
index b40a4a7e..dcbe9221 100644
--- a/core/pubnub_proxy_core.c
+++ b/core/pubnub_proxy_core.c
@@ -122,6 +122,15 @@ static int process_digest_header_line(pubnub_t* p, char const* header)
     return 0;
 }
 
+void pbproxy_handle_connection_close(pubnub_t *pb)
+{
+    /* Invalidate current NTLM proxy context state. */
+    if (pbhtauNTLM == pb->proxy_auth_scheme &&
+        (pb->ntlm_context.state != pbntlmSendNegotiate &&
+            pb->ntlm_context.state != pbntlmDone)) {
+        pbntlm_core_deinit(pb);
+    }
+}
     
 int pbproxy_handle_http_header(pubnub_t* p, char const* header)
 {
@@ -211,6 +220,7 @@ int pbproxy_handle_http_header(pubnub_t* p, char const* header)
     }
     else if ((0 == strncmp(contents, scheme_NTLM, sizeof scheme_NTLM - 1)) &&
              (auth_sheme_priority(p->proxy_auth_scheme) <= auth_sheme_priority(pbhtauNTLM))) {
+        PUBNUB_LOG_TRACE("pbproxy_handle_http_header() NTLM authentication\n");
         if (pbhtauNTLM != p->proxy_auth_scheme) {
             pbntlm_core_init(p);
             p->proxy_auth_scheme        = pbhtauNTLM;
diff --git a/core/pubnub_proxy_core.h b/core/pubnub_proxy_core.h
index e73c2772..6669192c 100644
--- a/core/pubnub_proxy_core.h
+++ b/core/pubnub_proxy_core.h
@@ -19,12 +19,15 @@
 
 
 #if PUBNUB_PROXY_API
+/** Handle PubNub context connection close. */
+void pbproxy_handle_connection_close(pubnub_t *pb);
 /** Processes a proxy related HTTP @p header on the Pubnub context @p
     p.
     @return 0 expected, -1 unexpected proxy authentication header
 */
 int pbproxy_handle_http_header(pubnub_t *p, char const* header);
 #else
+#define pbproxy_handle_connection_close(p, header)
 #define pbproxy_handle_http_header(p, header) 0
 #endif
 
diff --git a/core/pubnub_pubsubapi.c b/core/pubnub_pubsubapi.c
index ac9b027d..a8953a97 100644
--- a/core/pubnub_pubsubapi.c
+++ b/core/pubnub_pubsubapi.c
@@ -52,10 +52,8 @@ pubnub_t* pubnub_init(pubnub_t* p, const char* publish_key, const char* subscrib
     p->state                          = PBS_IDLE;
     p->trans                          = PBTT_NONE;
     p->options.use_http_keep_alive    = true;
-#if PUBNUB_USE_IPV6 && defined(PUBNUB_CALLBACK_API)
-    /* Connectivity type(true-Ipv6/false-Ipv4) chosen on given contex.
-       Ipv4 by default.
-     */
+#if PUBNUB_USE_IPV6
+    /* IPv4 connectivity type by default. */
     p->options.ipv6_connectivity = false;
 #endif
     p->flags.started_while_kept_alive = false;
@@ -110,7 +108,7 @@ enum pubnub_res pubnub_publish(pubnub_t* pb, const char* channel, const char* me
     }
 
     rslt = pbcc_publish_prep(
-        &pb->core, channel, message, true, false, NULL, SIZE_MAX, pubnubSendViaGET);
+        &pb->core, channel, message, NULL, true, false, NULL, SIZE_MAX, pubnubSendViaGET);
     if (PNR_STARTED == rslt) {
         pb->trans            = PBTT_PUBLISH;
         pb->core.last_result = PNR_STARTED;
@@ -137,7 +135,7 @@ enum pubnub_res pubnub_signal(pubnub_t* pb,
         return PNR_IN_PROGRESS;
     }
 
-    rslt = pbcc_signal_prep(&pb->core, channel, message);
+    rslt = pbcc_signal_prep(&pb->core, channel, message, NULL);
     if (PNR_STARTED == rslt) {
         pb->trans            = PBTT_SIGNAL;
         pb->core.last_result = PNR_STARTED;
diff --git a/core/pubnub_subscribe_v2_message.h b/core/pubnub_subscribe_v2_message.h
index bd02cbfb..4c712418 100644
--- a/core/pubnub_subscribe_v2_message.h
+++ b/core/pubnub_subscribe_v2_message.h
@@ -54,6 +54,8 @@ struct pubnub_v2_message {
     enum pubnub_message_type message_type;
     /** The message information about publisher */
     struct pubnub_char_mem_block publisher;
+    /** User-provided message type. */
+    struct pubnub_char_mem_block custom_message_type;
 };
 
 
diff --git a/core/pubnub_subscribe_v2_unit_test.c b/core/pubnub_subscribe_v2_unit_test.c
index eb89c06e..fad553bb 100644
--- a/core/pubnub_subscribe_v2_unit_test.c
+++ b/core/pubnub_subscribe_v2_unit_test.c
@@ -53,7 +53,7 @@ Ensure(subscribe_v2, should_parse_response_correctly) {
     assert_that(pubnub_auth_get(pbp), is_equal_to_string(NULL));
     expect_have_dns_for_pubnub_origin_on_ctx(pbp);
     expect_outgoing_with_url_on_ctx(pbp,
-        "/v2/subscribe/sub_key/my-channel/0?pnsdk=unit-test-0.1&tt=0&tr=0&uuid=test_id&heartbeat=270");
+        "/v2/subscribe/sub_key/my-channel/0?pnsdk=unit-test-0.1&tt=0&uuid=test_id&heartbeat=300");
     incoming("HTTP/1.1 200\r\nContent-Length: "
              "44\r\n\r\n{\"t\":{\"t\":\"15628652479932717\",\"r\":4},\"m\":[]}",
              NULL);
@@ -71,9 +71,9 @@ Ensure(subscribe_v2, should_parse_response_correctly) {
     expect(pbntf_got_socket, when(pb, is_equal_to(pbp)), will_return(0));
  
     expect_outgoing_with_url_on_ctx(pbp,
-        "/v2/subscribe/sub_key/my-channel/0?pnsdk=unit-test-0.1&tt=15628652479932717&tr=4&uuid=test_id&heartbeat=270");
+        "/v2/subscribe/sub_key/my-channel/0?pnsdk=unit-test-0.1&tt=15628652479932717&tr=4&uuid=test_id&heartbeat=300");
     incoming("HTTP/1.1 220\r\nContent-Length: "
-             "183\r\n\r\n{\"t\":{\"t\":\"15628652479932717\",\"r\":4},\"m\":[{\"a\":\"1\",\"f\":514,\"i\":\"publisher_id\",\"s\":1,\"p\":{\"t\":\"15628652479933927\",\"r\":4},\"k\":\"demo\",\"c\":\"my-channel\",\"d\":\"mymessage\",\"b\":\"my-channel\"}]}",
+             "209\r\n\r\n{\"t\":{\"t\":\"15628652479932717\",\"r\":4},\"m\":[{\"a\":\"1\",\"f\":514,\"cmt\":\"test-message-type\",\"i\":\"publisher_id\",\"s\":1,\"p\":{\"t\":\"15628652479933927\",\"r\":4},\"k\":\"demo\",\"c\":\"my-channel\",\"d\":\"mymessage\",\"b\":\"my-channel\"}]}",
              NULL);
 
     expect(pbntf_lost_socket, when(pb, is_equal_to(pbp)));
@@ -88,6 +88,7 @@ Ensure(subscribe_v2, should_parse_response_correctly) {
     assert_char_mem_block(msg.channel, "my-channel");
     assert_char_mem_block(msg.payload, "\"mymessage\"");
     assert_char_mem_block(msg.publisher, "publisher_id");
+    assert_char_mem_block(msg.custom_message_type, "test-message-type");
 
     assert_that(msg.region, is_equal_to(4));
     assert_that(msg.flags, is_equal_to(514));
diff --git a/core/pubnub_version_internal.h b/core/pubnub_version_internal.h
index ecd52c95..2512985b 100644
--- a/core/pubnub_version_internal.h
+++ b/core/pubnub_version_internal.h
@@ -3,7 +3,7 @@
 #define INC_PUBNUB_VERSION_INTERNAL
 
 
-#define PUBNUB_SDK_VERSION "4.14.1"
+#define PUBNUB_SDK_VERSION "4.15.0"
 
 
 #endif /* !defined INC_PUBNUB_VERSION_INTERNAL */
diff --git a/core/samples/publish_queue_callback_subloop.c b/core/samples/publish_queue_callback_subloop.c
index 927f41f8..cc8afec5 100644
--- a/core/samples/publish_queue_callback_subloop.c
+++ b/core/samples/publish_queue_callback_subloop.c
@@ -2,6 +2,7 @@
 #include "pubnub_callback.h"
 
 #include "core/pubnub_callback_subscribe_loop.h"
+#include "core/pubnub_coreapi.h"
 #include "core/pubnub_timers.h"
 #include "core/pubnub_helper.h"
 #include "core/pubnub_log.h"
@@ -158,6 +159,11 @@ int main()
     time_t                     start           = time(NULL);
     unsigned                   i               = 0;
 
+    char* my_env_ipv6_connectivity = getenv("PUBNUB_USE_IPV6_CONNECTIVITY");
+    char* my_env_origin = getenv("PUBNUB_ORIGIN");
+    if (NULL == my_env_origin) { my_env_origin = "ps.pndsn.com"; }
+    if (NULL == my_env_ipv6_connectivity) { my_env_ipv6_connectivity = "0"; }
+
     if ((NULL == pbp) || (NULL == pbp_2)) {
         printf("Failed to allocate Pubnub context(1 or 2)!\n");
         return -1;
@@ -168,6 +174,17 @@ int main()
     pubnub_set_user_id(pbp, "demo");
     pubnub_set_user_id(pbp_2, "demo_2");
 
+    pubnub_origin_set(pbp, my_env_origin);
+    pubnub_origin_set(pbp_2, my_env_origin);
+
+#if PUBNUB_USE_IPV6
+    // Enable IPv6 connectivity.
+    if (0 == strcmp(my_env_ipv6_connectivity, "1")) {
+        pubnub_set_ipv6_connectivity(pbp);
+        pubnub_set_ipv6_connectivity(pbp_2);
+    }
+#endif
+
     pubnub_register_callback(pbp_2, publish_callback, (void*)chan);
 
     pubnub_mutex_init_static(m_lock);
diff --git a/core/samples/pubnub_fetch_history_sample.c b/core/samples/pubnub_fetch_history_sample.c
index 03e19fd3..8cfb62b4 100644
--- a/core/samples/pubnub_fetch_history_sample.c
+++ b/core/samples/pubnub_fetch_history_sample.c
@@ -4,6 +4,7 @@
 #if PUBNUB_USE_FETCH_HISTORY
 #include "core/pubnub_fetch_history.c"
 #endif
+#include "core/pubnub_coreapi_ex.h"
 #include "core/pubnub_helper.h"
 #include "core/pubnub_timers.h"
 
@@ -58,9 +59,13 @@ static void publish_on_channels(pubnub_t* pbp)
         enum pubnub_res res;
         char msg[100];
         sprintf(msg,"\"Hello world from fetch history sample %d !\"", i);
-        res = pubnub_publish(pbp,
+        struct pubnub_publish_options opts = pubnub_publish_defopts();
+        opts.custom_message_type = "test-message-type";
+
+        res = pubnub_publish_ex(pbp,
                                 m_channel1,
-                                msg);
+                                msg,
+                                opts);
         if (res == PNR_STARTED) {
             puts("Await publish");
             res = pubnub_await(pbp);
@@ -139,6 +144,7 @@ int main(int argc, char* argv[])
              m_channel2);    
 
     struct pubnub_fetch_history_options opt = pubnub_fetch_history_defopts();
+    opt.include_custom_message_type = true;
     opt.include_message_type = true;
     opt.include_meta = true;
     res = pubnub_fetch_history(pbp, string_channels, opt);
@@ -162,6 +168,10 @@ int main(int argc, char* argv[])
             printf("\"meta\" is missing in response.");
             return 1;
         }
+        if (NULL == strstr(response.ptr, "\"custom_message_type\"")) {
+            printf("\"custom_message_type\" is missing in response.");
+            return 1;
+        }
     }
     else{
         printf("pubnub_fetch_history() failed with code: %d('%s')\n",
diff --git a/core/samples/pubnub_publish_via_post_sample.c b/core/samples/pubnub_publish_via_post_sample.c
index 4c60bd3d..2ba85c48 100644
--- a/core/samples/pubnub_publish_via_post_sample.c
+++ b/core/samples/pubnub_publish_via_post_sample.c
@@ -2,6 +2,7 @@
 #include "pubnub_sync.h"
 
 #include "core/pubnub_coreapi_ex.h"
+#include "core/pubnub_coreapi.h"
 #include "core/pubnub_helper.h"
 #include "core/pubnub_timers.h"
 
@@ -89,14 +90,25 @@ int main()
     char* my_env_publish_key = getenv("PUBNUB_PUBLISH_KEY");
     char* my_env_subscribe_key = getenv("PUBNUB_SUBSCRIBE_KEY");
     char* my_env_secret_key = getenv("PUBNUB_SECRET_KEY");
+    char* my_env_ipv6_connectivity = getenv("PUBNUB_USE_IPV6_CONNECTIVITY");
+    char* my_env_origin = getenv("PUBNUB_ORIGIN");
 
     if (NULL == my_env_publish_key) { my_env_publish_key = "demo"; }
     if (NULL == my_env_subscribe_key) { my_env_subscribe_key = "demo"; }
     if (NULL == my_env_secret_key) { my_env_secret_key = "demo"; }
+    if (NULL == my_env_origin) { my_env_origin = "ps.pndsn.com"; }
+    if (NULL == my_env_ipv6_connectivity) { my_env_ipv6_connectivity = "0"; }
     printf("%s\n%s\n%s\n",my_env_publish_key,my_env_subscribe_key,my_env_secret_key);
 
     pubnub_init(pbp, my_env_publish_key, my_env_subscribe_key);
     pubnub_set_user_id(pbp, user_id);
+    pubnub_origin_set(pbp, my_env_origin);
+#if PUBNUB_USE_IPV6
+    // Enable IPv6 connectivity.
+    if (0 == strcmp(my_env_ipv6_connectivity, "1")) {
+        pubnub_set_ipv6_connectivity(pbp);
+    }
+#endif
 
     pubnub_set_transaction_timeout(pbp, PUBNUB_DEFAULT_NON_SUBSCRIBE_TIMEOUT);
 
diff --git a/cpp/posix_openssl.mk b/cpp/posix_openssl.mk
index 12bb230e..5fa51c7e 100644
--- a/cpp/posix_openssl.mk
+++ b/cpp/posix_openssl.mk
@@ -118,14 +118,36 @@ CFLAGS =-g -I .. -I . -I ../openssl -I ../lib/base64 -Wall -D PUBNUB_THREADSAFE
 
 OS := $(shell uname)
 ifeq ($(OS),Darwin)
-SOURCEFILES += ../posix/monotonic_clock_get_time_darwin.c
-OBJFILES += monotonic_clock_get_time_darwin.o
-LDLIBS=-lpthread -lssl -lcrypto -L/usr/local/opt/openssl/lib
-CFLAGS += -I/usr/local/opt/openssl/include
+	SOURCEFILES += ../posix/monotonic_clock_get_time_darwin.c
+	OBJFILES += monotonic_clock_get_time_darwin.o
+	LDLIBS=-lpthread -lssl -lcrypto
+
+	# Ensure OpenSSL paths are set.
+	OPENSSL_CFLAGS := $(shell pkg-config --cflags openssl 2>/dev/null)
+	OPENSSL_LIBS := $(shell pkg-config --libs openssl 2>/dev/null)
+	ifneq ($(OPENSSL_CFLAGS),)
+		CFLAGS += $(OPENSSL_CFLAGS)
+	endif
+	ifneq ($(OPENSSL_LIBS),)
+		LDLIBS += $(OPENSSL_LIBS)
+	endif
 else
-SOURCEFILES += ../posix/monotonic_clock_get_time_posix.c
-OBJFILES += monotonic_clock_get_time_posix.o
-LDLIBS=-lrt -lpthread -lssl -lcrypto
+	SOURCEFILES += ../posix/monotonic_clock_get_time_posix.c
+	OBJFILES += monotonic_clock_get_time_posix.o
+	LDLIBS=-lrt -lpthread -lssl -lcrypto
+
+	ifeq ($(shell test -d "/usr/local/opt/openssl" && echo yes || echo no),yes)
+		CFLAGS += -I/usr/local/opt/openssl/include
+	else
+		# Path on GitHub Action Runner (ubuntu-latest image)
+		ifeq ($(shell test -d "/usr/include/openssl" && echo yes || echo no),yes)
+			CFLAGS += -I/usr/include
+		endif
+	endif
+	# Path on GitHub Action Runner (ubuntu-latest image)
+	ifeq ($(shell test -d "/usr/lib/x86_64-linux-gnu" && echo yes || echo no),yes)
+		LDLIBS += -L/usr/lib/x86_64-linux-gnu
+	endif
 endif
 
 
diff --git a/lib/sockets/pbpal_resolv_and_connect_sockets.c b/lib/sockets/pbpal_resolv_and_connect_sockets.c
index f89e8580..ad4b0517 100644
--- a/lib/sockets/pbpal_resolv_and_connect_sockets.c
+++ b/lib/sockets/pbpal_resolv_and_connect_sockets.c
@@ -149,6 +149,7 @@ static void get_dns_ip(struct sockaddr* addr)
         get_default_dns_ip((struct pubnub_ipv4_address*)p);
 #endif /* PUBNUB_USE_IPV6 */
     }
+#if PUBNUB_USE_IPV6
     if (AF_INET6 == addr->sa_family) {
         if ((pubnub_get_dns_primary_server_ipv6((struct pubnub_ipv6_address*)pv6)
              == -1)
@@ -158,6 +159,7 @@ static void get_dns_ip(struct sockaddr* addr)
             get_default_dns_ip((struct pubnub_ipv4_address*)p);
         }
     }
+#endif
 }
 #endif /* PUBNUB_CHANGE_DNS_SERVERS */
 #else
@@ -295,7 +297,11 @@ try_TCP_connect_spare_address(pb_socket_t*                   skt,
     enum pbpal_resolv_n_connect_result rslt = pbpal_resolv_resource_failure;
     time_t                             tt   = time(NULL);
 
-    if (spare_addresses->ipv4_index < spare_addresses->n_ipv4) {
+    if (spare_addresses->ipv4_index < spare_addresses->n_ipv4
+#if PUBNUB_USE_IPV6
+        && !options->ipv6_connectivity
+#endif /* PUBNUB_USE_IPV6 */
+        ) {
         PUBNUB_LOG_TRACE(
             "spare_addresses->ipv4_index = %d, spare_addresses->n_ipv4 = %d.\n",
             spare_addresses->ipv4_index,
@@ -408,10 +414,18 @@ enum pbpal_resolv_n_connect_result pbpal_resolv_and_connect(pubnub_t* pb)
 
 #ifdef PUBNUB_CALLBACK_API
     sockaddr_inX_t dest = { 0 };
+#if PUBNUB_USE_IPV6
+    const bool has_ipv6_proxy = 0 != pb->proxy_ipv6_address.ipv6[0]
+        || 0 != pb->proxy_ipv6_address.ipv6[1];
+#endif /* PUBNUB_USE_IPV6 */
 
     prepare_port_and_hostname(pb, &port, &origin);
 #if PUBNUB_PROXY_API
-    if (0 != pb->proxy_ipv4_address.ipv4[0]) {
+    if (0 != pb->proxy_ipv4_address.ipv4[0]
+#if PUBNUB_USE_IPV6
+        && (!pb->options.ipv6_connectivity || !has_ipv6_proxy)
+#endif /* PUBNUB_USE_IPV6 */
+        ) {
         struct sockaddr_in dest = { 0 };
         PUBNUB_LOG_TRACE("(0 != pb->proxy_ipv4_address.ipv4[0]) - ");
         memcpy(&(dest.sin_addr.s_addr),
@@ -422,8 +436,7 @@ enum pbpal_resolv_n_connect_result pbpal_resolv_and_connect(pubnub_t* pb)
             &pb->pal.socket, &pb->options, (struct sockaddr*)&dest, port);
     }
 #if PUBNUB_USE_IPV6
-    else if ((0 != pb->proxy_ipv6_address.ipv6[0])
-             || (0 != pb->proxy_ipv6_address.ipv6[1])) {
+    if (has_ipv6_proxy) {
         struct sockaddr_in6 dest = { 0 };
         PUBNUB_LOG_TRACE("(0 != pb->proxy_ipv6_address.ipv6[0]) ||"
                          " (0 != pb->proxy_ipv6_address.ipv6[1]) - ");
@@ -469,7 +482,7 @@ enum pbpal_resolv_n_connect_result pbpal_resolv_and_connect(pubnub_t* pb)
 #endif
         return pbpal_resolv_failed_send;
     }
-    else if (error > 0) {
+    if (error > 0) {
         return pbpal_resolv_send_wouldblock;
     }
     pb->flags.sent_queries++;
@@ -495,28 +508,41 @@ enum pbpal_resolv_n_connect_result pbpal_resolv_and_connect(pubnub_t* pb)
     if (error != 0) {
         return pbpal_resolv_failed_processing;
     }
+#if PUBNUB_USE_IPV6
+    for (int pass = 0; pass < 2; ++pass) {
+        bool prioritize_ipv6 = pass == 0 && pb->options.ipv6_connectivity;
+#endif /* PUBNUB_USE_IPV6 */
 
-    for (it = result; it != NULL; it = it->ai_next) {
-        pb->pal.socket = socket(it->ai_family, it->ai_socktype, it->ai_protocol);
-        if (pb->pal.socket == SOCKET_INVALID) {
-            continue;
-        }
-        pbpal_set_blocking_io(pb);
-        if (connect(pb->pal.socket, it->ai_addr, it->ai_addrlen) == SOCKET_ERROR) {
-            if (socket_would_block()) {
-                error = 1;
-                break;
-            }
-            else {
-                PUBNUB_LOG_WARNING("socket connect() failed, will try another "
-                                   "IP address, if available\n");
-                socket_close(pb->pal.socket);
-                pb->pal.socket = SOCKET_INVALID;
+        for (it = result; it != NULL; it = it->ai_next) {
+#if PUBNUB_USE_IPV6
+            if (prioritize_ipv6 && it->ai_family != AF_INET6) { continue; }
+            if (!prioritize_ipv6 && it->ai_family != AF_INET) { continue; }
+#endif /* PUBNUB_USE_IPV6 */
+
+            pb->pal.socket =
+                socket(it->ai_family, it->ai_socktype, it->ai_protocol);
+            if (pb->pal.socket == SOCKET_INVALID) {
                 continue;
             }
+            pbpal_set_blocking_io(pb);
+            if (connect(pb->pal.socket, it->ai_addr, it->ai_addrlen) == SOCKET_ERROR) {
+                if (socket_would_block()) {
+                    error = 1;
+                    break;
+                }
+                else {
+                    PUBNUB_LOG_WARNING("socket connect() failed, will try "
+                                       "another IP address, if available\n");
+                    socket_close(pb->pal.socket);
+                    pb->pal.socket = SOCKET_INVALID;
+                    continue;
+                }
+            }
+            break;
         }
-        break;
+#if PUBNUB_USE_IPV6
     }
+#endif /* PUBNUB_USE_IPV6 */
     freeaddrinfo(result);
 
     if (NULL == it) {
diff --git a/microchip_harmony/pbpal_resolv_and_connect_harmony_tcp.c b/microchip_harmony/pbpal_resolv_and_connect_harmony_tcp.c
index b5f26af8..c754cb92 100644
--- a/microchip_harmony/pbpal_resolv_and_connect_harmony_tcp.c
+++ b/microchip_harmony/pbpal_resolv_and_connect_harmony_tcp.c
@@ -13,7 +13,13 @@
 enum pbpal_resolv_n_connect_result pbpal_resolv_and_connect(pubnub_t *pb)
 {
     char const* origin = PUBNUB_ORIGIN_SETTABLE ? pb->origin : PUBNUB_ORIGIN;
-    TCPIP_DNS_RESULT dns_result = TCPIP_DNS_Resolve(origin, TCPIP_DNS_TYPE_A);
+#if PUBNUB_USE_IPV6
+    TCPIP_DNS_RESOLVE_TYPE query_type =
+        pb->options.ipv6_connectivity ? TCPIP_DNS_TYPE_AAAA : TCPIP_DNS_TYPE_A;
+#else
+    TCPIP_DNS_RESOLVE_TYPE query_type = TCPIP_DNS_TYPE_A;
+#endif
+    TCPIP_DNS_RESULT dns_result = TCPIP_DNS_Resolve(origin, query_type);
     PUBNUB_ASSERT(pb_valid_ctx_ptr(pb));
     PUBNUB_ASSERT((pb->state == PBS_IDLE) || (pb->state == PBS_WAIT_DNS_SEND) 
             || (pb->state == PBS_WAIT_DNS_RCV));
@@ -41,8 +47,14 @@ enum pbpal_resolv_n_connect_result pbpal_resolv_and_connect(pubnub_t *pb)
 enum pbpal_resolv_n_connect_result pbpal_check_resolv_and_connect(pubnub_t *pb)
 {
     char const* origin = PUBNUB_ORIGIN_SETTABLE ? pb->origin : PUBNUB_ORIGIN;
+#if PUBNUB_USE_IPV6
+    IP_ADDRESS_TYPE address_type =
+        pb->options.ipv6_connectivity ? IP_ADDRESS_TYPE_IPV6 : IP_ADDRESS_TYPE_IPV4;
+#else
+    IP_ADDRESS_TYPE address_type = IP_ADDRESS_TYPE_IPV4;
+#endif
     IP_MULTI_ADDRESS ip_addr;
-    TCPIP_DNS_RESULT dns_result = TCPIP_DNS_IsResolved(origin, &ip_addr, IP_ADDRESS_TYPE_IPV4);
+    TCPIP_DNS_RESULT dns_result = TCPIP_DNS_IsResolved(origin, &ip_addr, address_type);
 	PUBNUB_ASSERT_OPT(pb != NULL);
     switch (dns_result) {
         case TCPIP_DNS_RES_OK:
@@ -51,12 +63,12 @@ enum pbpal_resolv_n_connect_result pbpal_check_resolv_and_connect(pubnub_t *pb)
                 pb->pal.socket = NET_PRES_SocketOpen(
                         0, 
                         pb->options.useSSL ? NET_PRES_SKT_ENCRYPTED_STREAM_CLIENT : NET_PRES_SKT_UNENCRYPTED_STREAM_CLIENT,
-                        IP_ADDRESS_TYPE_IPV4, 
+                        address_type,
                         HTTPS_PORT, 
                         (NET_PRES_ADDRESS*)&ip_addr, NULL
                         );
 #else
-                pb->pal.socket = TCPIP_TCP_ClientOpen(IP_ADDRESS_TYPE_IPV4, HTTP_PORT, &ip_addr);
+                pb->pal.socket = TCPIP_TCP_ClientOpen(address_type, HTTP_PORT, &ip_addr);
 #endif
             }
             if (SOCKET_INVALID == pb->pal.socket) {
diff --git a/openssl/posix.mk b/openssl/posix.mk
index 445d083b..5f96541f 100644
--- a/openssl/posix.mk
+++ b/openssl/posix.mk
@@ -58,6 +58,14 @@ ifndef USE_CRYPTO_API
 USE_CRYPTO_API = 1
 endif
 
+ifndef USE_IPV6
+USE_IPV6 = 1
+endif
+
+ifndef USE_DNS_SERVERS
+USE_DNS_SERVERS = 1
+endif
+
 ifeq ($(USE_PROXY), 1)
 SOURCEFILES += ../core/pubnub_proxy.c ../core/pubnub_proxy_core.c ../core/pbhttp_digest.c ../core/pbntlm_core.c ../core/pbntlm_packer_std.c
 OBJFILES += pubnub_proxy.o pubnub_proxy_core.o pbhttp_digest.o pbntlm_core.o pbntlm_packer_std.o
@@ -125,43 +133,61 @@ CFLAGS = -g -D PUBNUB_THREADSAFE -D PUBNUB_LOG_LEVEL=PUBNUB_LOG_LEVEL_WARNING -W
 
 OS := $(shell uname)
 ifeq ($(OS),Darwin)
-SOURCEFILES += ../posix/monotonic_clock_get_time_darwin.c
-OBJFILES += monotonic_clock_get_time_darwin.o
-LDLIBS = -lpthread -lssl -lcrypto -L/usr/local/opt/openssl/lib
-CFLAGS += -I/usr/local/opt/openssl/include
+	SOURCEFILES += ../posix/monotonic_clock_get_time_darwin.c
+	OBJFILES += monotonic_clock_get_time_darwin.o
+	LDLIBS = -lpthread -lssl -lcrypto
+
+	# Ensure OpenSSL paths are set.
+	OPENSSL_CFLAGS := $(shell pkg-config --cflags openssl 2>/dev/null)
+	OPENSSL_LIBS := $(shell pkg-config --libs openssl 2>/dev/null)
+	ifneq ($(OPENSSL_CFLAGS),)
+		CFLAGS += $(OPENSSL_CFLAGS)
+	endif
+	ifneq ($(OPENSSL_LIBS),)
+		LDLIBS += $(OPENSSL_LIBS)
+	endif
 else
-SOURCEFILES += ../posix/monotonic_clock_get_time_posix.c
-OBJFILES += monotonic_clock_get_time_posix.o
-LDLIBS=-lrt -lpthread -lssl -lcrypto
+	SOURCEFILES += ../posix/monotonic_clock_get_time_posix.c
+	OBJFILES += monotonic_clock_get_time_posix.o
+	LDLIBS=-lrt -lpthread -lssl -lcrypto
+
+	ifeq ($(shell test -d "/usr/local/opt/openssl" && echo yes || echo no),yes)
+		CFLAGS += -I/usr/local/opt/openssl/include
+	else
+		# Path on GitHub Action Runner (ubuntu-latest image)
+		ifeq ($(shell test -d "/usr/include/openssl" && echo yes || echo no),yes)
+			CFLAGS += -I/usr/include
+		endif
+	endif
+	# Path on GitHub Action Runner (ubuntu-latest image)
+	ifeq ($(shell test -d "/usr/lib/x86_64-linux-gnu" && echo yes || echo no),yes)
+		LDLIBS += -L/usr/lib/x86_64-linux-gnu
+	endif
 endif
 
-
 INCLUDES=-I .. -I . -I ../lib/base64/
 
-
 all: pubnub_sync_sample pubnub_sync_grant_token_sample pubnub_sync_revoke_token_sample pubnub_objects_secretkey_sample metadata cancel_subscribe_sync_sample pubnub_sync_subloop_sample pubnub_publish_via_post_sample pubnub_publish_via_post_secretkey_sample pubnub_advanced_history_sample pubnub_fetch_history_sample pubnub_callback_sample subscribe_publish_callback_sample pubnub_callback_subloop_sample pubnub_fntest pubnub_console_sync pubnub_console_callback pubnub_crypto_sync_sample subscribe_publish_from_callback publish_callback_subloop_sample publish_queue_callback_subloop pubnub_crypto_module_sample
 
 SYNC_INTF_SOURCEFILES=../core/pubnub_ntf_sync.c ../core/pubnub_sync_subscribe_loop.c ../core/srand_from_pubnub_time.c
 SYNC_INTF_OBJFILES=pubnub_ntf_sync.o pubnub_sync_subscribe_loop.o srand_from_pubnub_time.o
 
+ifeq ($(USE_IPV6), 1)
+SYNC_INTF_SOURCEFILES += ../lib/pubnub_parse_ipv6_addr.c
+SYNC_INTF_OBJFILES += pubnub_parse_ipv6_addr.o
+endif
+
 pubnub_sync.a : $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES) $(REVOKE_TOKEN_SOURCEFILES) $(GRANT_TOKEN_SOURCEFILES)
-	$(CC) -c $(CFLAGS) -D PUBNUB_RAND_INIT_VECTOR=0 $(INCLUDES) $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES) $(REVOKE_TOKEN_SOURCEFILES) $(GRANT_TOKEN_SOURCEFILES)
+	$(CC) -c $(CFLAGS) -D PUBNUB_USE_IPV6=$(USE_IPV6) -D PUBNUB_RAND_INIT_VECTOR=0 $(INCLUDES) $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES) $(REVOKE_TOKEN_SOURCEFILES) $(GRANT_TOKEN_SOURCEFILES)
 	ar rcs pubnub_sync.a $(OBJFILES) $(SYNC_INTF_OBJFILES) $(REVOKE_TOKEN_OBJFILES) $(GRANT_TOKEN_OBJFILES)
 
 pubnub_sync_dynamiciv.a : $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES) $(REVOKE_TOKEN_SOURCEFILES) $(GRANT_TOKEN_SOURCEFILES)
-	$(CC) -c $(CFLAGS) -D PUBNUB_RAND_INIT_VECTOR=1 $(INCLUDES) $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES) $(REVOKE_TOKEN_SOURCEFILES) $(GRANT_TOKEN_SOURCEFILES)
+	$(CC) -c $(CFLAGS) -D PUBNUB_USE_IPV6=$(USE_IPV6) -D PUBNUB_RAND_INIT_VECTOR=1 $(INCLUDES) $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES) $(REVOKE_TOKEN_SOURCEFILES) $(GRANT_TOKEN_SOURCEFILES)
 	ar rcs pubnub_sync_dynamiciv.a $(OBJFILES) $(SYNC_INTF_OBJFILES) $(REVOKE_TOKEN_OBJFILES) $(GRANT_TOKEN_OBJFILES)
 
 CALLBACK_INTF_SOURCEFILES=pubnub_ntf_callback_posix.c pubnub_get_native_socket.c ../core/pubnub_timer_list.c ../lib/sockets/pbpal_ntf_callback_poller_poll.c ../lib/sockets/pbpal_adns_sockets.c ../lib/pubnub_dns_codec.c ../core/pbpal_ntf_callback_queue.c ../core/pbpal_ntf_callback_admin.c ../core/pbpal_ntf_callback_handle_timer_list.c  ../core/pubnub_callback_subscribe_loop.c
 CALLBACK_INTF_OBJFILES=pubnub_ntf_callback_posix.o pubnub_get_native_socket.o pubnub_timer_list.o pbpal_ntf_callback_poller_poll.o pbpal_adns_sockets.o pubnub_dns_codec.o pbpal_ntf_callback_queue.o pbpal_ntf_callback_admin.o pbpal_ntf_callback_handle_timer_list.o pubnub_callback_subscribe_loop.o
 
-ifndef USE_DNS_SERVERS
-USE_DNS_SERVERS = 1
-endif
-
-ifndef USE_IPV6
-USE_IPV6 = 1
-endif
 
 ifeq ($(USE_DNS_SERVERS), 1)
 CALLBACK_INTF_SOURCEFILES += ../core/pubnub_dns_servers.c ../posix/pubnub_dns_system_servers.c ../lib/pubnub_parse_ipv4_addr.c
@@ -216,7 +242,7 @@ pubnub_sync_subloop_sample: ../core/samples/pubnub_sync_subloop_sample.c pubnub_
 	$(CC) -o $@ $(CFLAGS) $(INCLUDES) ../core/samples/pubnub_sync_subloop_sample.c pubnub_sync.a $(LDLIBS)
 
 pubnub_publish_via_post_sample: ../core/samples/pubnub_publish_via_post_sample.c pubnub_sync.a
-	$(CC) -o $@ $(CFLAGS) $(INCLUDES) ../core/samples/pubnub_publish_via_post_sample.c pubnub_sync.a $(LDLIBS)
+	$(CC) -o $@ $(CFLAGS) -D PUBNUB_USE_IPV6=$(USE_IPV6) $(INCLUDES) ../core/samples/pubnub_publish_via_post_sample.c pubnub_sync.a $(LDLIBS)
 
 pubnub_publish_via_post_secretkey_sample: ../core/samples/pubnub_publish_via_post_secretkey_sample.c pubnub_sync.a
 	$(CC) -o $@ $(CFLAGS) $(INCLUDES) ../core/samples/pubnub_publish_via_post_secretkey_sample.c pubnub_sync.a $(LDLIBS)
@@ -243,7 +269,7 @@ publish_callback_subloop_sample: ../core/samples/publish_callback_subloop_sample
 	$(CC) -o $@ -D PUBNUB_CALLBACK_API $(CFLAGS) $(CFLAGS_CALLBACK) $(INCLUDES) ../core/samples/publish_callback_subloop_sample.c pubnub_callback.a $(LDLIBS)
 
 publish_queue_callback_subloop: ../core/samples/publish_queue_callback_subloop.c pubnub_callback.a
-	$(CC) -o $@ -D PUBNUB_CALLBACK_API $(CFLAGS) $(CFLAGS_CALLBACK) $(INCLUDES) ../core/samples/publish_queue_callback_subloop.c pubnub_callback.a $(LDLIBS)
+	$(CC) -o $@ -D PUBNUB_CALLBACK_API $(CFLAGS) -D PUBNUB_USE_IPV6=$(USE_IPV6) $(CFLAGS_CALLBACK) $(INCLUDES) ../core/samples/publish_queue_callback_subloop.c pubnub_callback.a $(LDLIBS)
 
 pubnub_crypto_module_sample: ../core/samples/pubnub_crypto_module_sample.c pubnub_sync.a
 	$(CC) -o $@ $(CFLAGS) $(INCLUDES) -I ../core/ ../core/samples/pubnub_crypto_module_sample.c pubnub_sync.a $(LDLIBS)
diff --git a/posix/posix.mk b/posix/posix.mk
index 80cc008a..0a1cab5f 100644
--- a/posix/posix.mk
+++ b/posix/posix.mk
@@ -58,6 +58,14 @@ ifndef USE_FETCH_HISTORY
 USE_FETCH_HISTORY = 1
 endif
 
+ifndef USE_IPV6
+USE_IPV6 = 1
+endif
+
+ifndef USE_DNS_SERVERS
+USE_DNS_SERVERS = 1
+endif
+
 ifeq ($(USE_PROXY), 1)
 SOURCEFILES += ../core/pubnub_proxy.c ../core/pubnub_proxy_core.c ../core/pbhttp_digest.c ../core/pbntlm_core.c ../core/pbntlm_packer_std.c
 OBJFILES += pubnub_proxy.o pubnub_proxy_core.o pbhttp_digest.o pbntlm_core.o pbntlm_packer_std.o
@@ -136,20 +144,18 @@ all: pubnub_sync_sample metadata cancel_subscribe_sync_sample pubnub_advanced_hi
 SYNC_INTF_SOURCEFILES=../core/pubnub_ntf_sync.c ../core/pubnub_sync_subscribe_loop.c ../core/srand_from_pubnub_time.c
 SYNC_INTF_OBJFILES=pubnub_ntf_sync.o pubnub_sync_subscribe_loop.o srand_from_pubnub_time.o
 
+ifeq ($(USE_IPV6), 1)
+SYNC_INTF_SOURCEFILES += ../lib/pubnub_parse_ipv6_addr.c
+SYNC_INTF_OBJFILES += pubnub_parse_ipv6_addr.o
+endif
+
 pubnub_sync.a : $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES)
-	$(CC) -c $(CFLAGS) $(INCLUDES) $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES)
+	$(CC) -c $(CFLAGS) -D PUBNUB_USE_IPV6=$(USE_IPV6) $(INCLUDES) $(SOURCEFILES) $(SYNC_INTF_SOURCEFILES)
 	ar rcs pubnub_sync.a $(OBJFILES) $(SYNC_INTF_OBJFILES)
 
 CALLBACK_INTF_SOURCEFILES=pubnub_ntf_callback_posix.c pubnub_get_native_socket.c ../core/pubnub_timer_list.c ../lib/sockets/pbpal_ntf_callback_poller_poll.c ../lib/sockets/pbpal_adns_sockets.c ../lib/pubnub_dns_codec.c ../core/pbpal_ntf_callback_queue.c ../core/pbpal_ntf_callback_admin.c ../core/pbpal_ntf_callback_handle_timer_list.c  ../core/pubnub_callback_subscribe_loop.c
 CALLBACK_INTF_OBJFILES=pubnub_ntf_callback_posix.o pubnub_get_native_socket.o pubnub_timer_list.o pbpal_ntf_callback_poller_poll.o pbpal_adns_sockets.o pubnub_dns_codec.o pbpal_ntf_callback_queue.o pbpal_ntf_callback_admin.o pbpal_ntf_callback_handle_timer_list.o pubnub_callback_subscribe_loop.o
 
-ifndef USE_DNS_SERVERS
-USE_DNS_SERVERS = 1
-endif
-
-ifndef USE_IPV6
-USE_IPV6 = 1
-endif
 
 ifeq ($(USE_DNS_SERVERS), 1)
 CALLBACK_INTF_SOURCEFILES += ../core/pubnub_dns_servers.c ../posix/pubnub_dns_system_servers.c ../lib/pubnub_parse_ipv4_addr.c
@@ -183,7 +189,7 @@ pubnub_sync_publish_retry: ../core/samples/pubnub_sync_publish_retry.c pubnub_sy
 	$(CC) -o $@ $(CFLAGS) $(INCLUDES) ../core/samples/pubnub_sync_publish_retry.c pubnub_sync.a $(LDLIBS)
 
 pubnub_publish_via_post_sample: ../core/samples/pubnub_publish_via_post_sample.c pubnub_sync.a
-	$(CC) -o $@ $(CFLAGS) $(INCLUDES) ../core/samples/pubnub_publish_via_post_sample.c pubnub_sync.a $(LDLIBS)
+	$(CC) -o $@ $(CFLAGS) -D PUBNUB_USE_IPV6=$(USE_IPV6) $(INCLUDES) ../core/samples/pubnub_publish_via_post_sample.c pubnub_sync.a $(LDLIBS)
 
 pubnub_advanced_history_sample: ../core/samples/pubnub_advanced_history_sample.c pubnub_sync.a
 	$(CC) -o $@ $(CFLAGS) $(INCLUDES) ../core/samples/pubnub_advanced_history_sample.c pubnub_sync.a $(LDLIBS)
@@ -214,7 +220,7 @@ publish_callback_subloop_sample: ../core/samples/publish_callback_subloop_sample
 	$(CC) -o $@ -D PUBNUB_CALLBACK_API $(CFLAGS) $(CFLAGS_CALLBACK) $(INCLUDES) ../core/samples/publish_callback_subloop_sample.c pubnub_callback.a $(LDLIBS)
 
 publish_queue_callback_subloop: ../core/samples/publish_queue_callback_subloop.c pubnub_callback.a
-	$(CC) -o $@ -D PUBNUB_CALLBACK_API $(CFLAGS) $(CFLAGS_CALLBACK) $(INCLUDES) ../core/samples/publish_queue_callback_subloop.c pubnub_callback.a $(LDLIBS)
+	$(CC) -o $@ -D PUBNUB_CALLBACK_API $(CFLAGS) -D PUBNUB_USE_IPV6=$(USE_IPV6) $(CFLAGS_CALLBACK) $(INCLUDES) ../core/samples/publish_queue_callback_subloop.c pubnub_callback.a $(LDLIBS)
 
 pubnub_fntest: ../core/fntest/pubnub_fntest.c ../core/fntest/pubnub_fntest_basic.c ../core/fntest/pubnub_fntest_medium.c fntest/pubnub_fntest_posix.c fntest/pubnub_fntest_runner.c pubnub_sync.a
 	$(CC) -o $@ $(CFLAGS) $(INCLUDES) ../core/fntest/pubnub_fntest.c ../core/fntest/pubnub_fntest_basic.c ../core/fntest/pubnub_fntest_medium.c  fntest/pubnub_fntest_posix.c fntest/pubnub_fntest_runner.c pubnub_sync.a $(LDLIBS) -lpthread