diff --git a/libril/ril.cpp b/libril/ril.cpp
index cf32242..738eda5 100644
--- a/libril/ril.cpp
+++ b/libril/ril.cpp
@@ -202,6 +202,8 @@
 static void dispatchRaw(Parcel& p, RequestInfo *pRI);
 static void dispatchSmsWrite (Parcel &p, RequestInfo *pRI);
 static void dispatchDataCall (Parcel& p, RequestInfo *pRI);
+static void dispatchVoiceRadioTech (Parcel& p, RequestInfo *pRI);
+static void dispatchCdmaSubscriptionSource (Parcel& p, RequestInfo *pRI);
 
 static void dispatchCdmaSms(Parcel &p, RequestInfo *pRI);
 static void dispatchCdmaSmsAck(Parcel &p, RequestInfo *pRI);
@@ -231,6 +233,10 @@
 static int responseCdmaSignalInfoRecord(Parcel &p,void *response, size_t responselen);
 static int responseCdmaCallWaiting(Parcel &p,void *response, size_t responselen);
 
+static int decodeVoiceRadioTechnology (RIL_RadioState radioState);
+static int decodeCdmaSubscriptionSource (RIL_RadioState radioState);
+static RIL_RadioState processRadioState(RIL_RadioState newRadioState);
+
 extern "C" const char * requestToString(int request);
 extern "C" const char * failCauseToString(RIL_Errno);
 extern "C" const char * callStateToString(RIL_CallState);
@@ -254,6 +260,25 @@
 #include "ril_unsol_commands.h"
 };
 
+/* For older RILs that do not support new commands RIL_REQUEST_VOICE_RADIO_TECH and
+   RIL_UNSOL_VOICE_RADIO_TECH_CHANGED messages, decode the voice radio tech from
+   radio state message and store it. Every time there is a change in Radio State
+   check to see if voice radio tech changes and notify telephony
+ */
+int voiceRadioTech = -1;
+
+/* For older RILs that do not support new commands RIL_REQUEST_GET_CDMA_SUBSCRIPTION_SOURCE
+   and RIL_UNSOL_CDMA_SUBSCRIPTION_SOURCE_CHANGED messages, decode the subscription
+   source from radio state and store it. Every time there is a change in Radio State
+   check to see if subscription source changed and notify telephony
+ */
+int cdmaSubscriptionSource = -1;
+
+/* For older RILs that do not send RIL_UNSOL_RESPONSE_SIM_STATUS_CHANGED, decode the
+   SIM/RUIM state from radio state and store it. Every time there is a change in Radio State,
+   check to see if SIM/RUIM status changed and notify telephony
+ */
+int simRuimStatus = -1;
 
 static char *
 strdupReadString(Parcel &p) {
@@ -1219,6 +1244,60 @@
     }
 }
 
+// For backwards compatibility with RILs that dont support RIL_REQUEST_VOICE_RADIO_TECH.
+// When all RILs handle this request, this function can be removed and
+// the request can be sent directly to the RIL using dispatchVoid.
+static void dispatchVoiceRadioTech(Parcel& p, RequestInfo *pRI) {
+    RIL_RadioState state = s_callbacks.onStateRequest();
+
+    if ((RADIO_STATE_UNAVAILABLE == state) || (RADIO_STATE_OFF == state)) {
+        RIL_onRequestComplete(pRI, RIL_E_RADIO_NOT_AVAILABLE, NULL, 0);
+    }
+
+    // RILs that support RADIO_STATE_ON should support this request.
+    if (RADIO_STATE_ON == state) {
+        dispatchVoid(p, pRI);
+        return;
+    }
+
+    // For Older RILs, that do not support RADIO_STATE_ON, assume that they
+    // will not support this new request either and decode Voice Radio Technology
+    // from Radio State
+    voiceRadioTech = decodeVoiceRadioTechnology(state);
+
+    if (voiceRadioTech < 0)
+        RIL_onRequestComplete(pRI, RIL_E_GENERIC_FAILURE, NULL, 0);
+    else
+        RIL_onRequestComplete(pRI, RIL_E_SUCCESS, &voiceRadioTech, sizeof(int));
+}
+
+// For backwards compatibility in RIL_REQUEST_CDMA_GET_SUBSCRIPTION_SOURCE:.
+// When all RILs handle this request, this function can be removed and
+// the request can be sent directly to the RIL using dispatchVoid.
+static void dispatchCdmaSubscriptionSource(Parcel& p, RequestInfo *pRI) {
+    RIL_RadioState state = s_callbacks.onStateRequest();
+
+    if ((RADIO_STATE_UNAVAILABLE == state) || (RADIO_STATE_OFF == state)) {
+        RIL_onRequestComplete(pRI, RIL_E_RADIO_NOT_AVAILABLE, NULL, 0);
+    }
+
+    // RILs that support RADIO_STATE_ON should support this request.
+    if (RADIO_STATE_ON == state) {
+        dispatchVoid(p, pRI);
+        return;
+    }
+
+    // For Older RILs, that do not support RADIO_STATE_ON, assume that they
+    // will not support this new request either and decode CDMA Subscription Source
+    // from Radio State
+    cdmaSubscriptionSource = decodeCdmaSubscriptionSource(state);
+
+    if (cdmaSubscriptionSource < 0)
+        RIL_onRequestComplete(pRI, RIL_E_GENERIC_FAILURE, NULL, 0);
+    else
+        RIL_onRequestComplete(pRI, RIL_E_SUCCESS, &cdmaSubscriptionSource, sizeof(int));
+}
+
 static int
 blockingWrite(int fd, const void *buffer, size_t len) {
     size_t writeOffset = 0;
@@ -2866,6 +2945,123 @@
     }
 }
 
+static int
+decodeVoiceRadioTechnology (RIL_RadioState radioState) {
+    switch (radioState) {
+        case RADIO_STATE_SIM_NOT_READY:
+        case RADIO_STATE_SIM_LOCKED_OR_ABSENT:
+        case RADIO_STATE_SIM_READY:
+            return RADIO_TECH_UMTS;
+
+        case RADIO_STATE_RUIM_NOT_READY:
+        case RADIO_STATE_RUIM_READY:
+        case RADIO_STATE_RUIM_LOCKED_OR_ABSENT:
+        case RADIO_STATE_NV_NOT_READY:
+        case RADIO_STATE_NV_READY:
+            return RADIO_TECH_1xRTT;
+
+        default:
+            LOGD("decodeVoiceRadioTechnology: Invoked with incorrect RadioState");
+            return -1;
+    }
+}
+
+static int
+decodeCdmaSubscriptionSource (RIL_RadioState radioState) {
+    switch (radioState) {
+        case RADIO_STATE_SIM_NOT_READY:
+        case RADIO_STATE_SIM_LOCKED_OR_ABSENT:
+        case RADIO_STATE_SIM_READY:
+        case RADIO_STATE_RUIM_NOT_READY:
+        case RADIO_STATE_RUIM_READY:
+        case RADIO_STATE_RUIM_LOCKED_OR_ABSENT:
+            return CDMA_SUBSCRIPTION_SOURCE_RUIM_SIM;
+
+        case RADIO_STATE_NV_NOT_READY:
+        case RADIO_STATE_NV_READY:
+            return CDMA_SUBSCRIPTION_SOURCE_NV;
+
+        default:
+            LOGD("decodeCdmaSubscriptionSource: Invoked with incorrect RadioState");
+            return -1;
+    }
+}
+
+static int
+decodeSimStatus (RIL_RadioState radioState) {
+   switch (radioState) {
+       case RADIO_STATE_SIM_NOT_READY:
+       case RADIO_STATE_RUIM_NOT_READY:
+       case RADIO_STATE_NV_NOT_READY:
+       case RADIO_STATE_NV_READY:
+           return -1;
+       case RADIO_STATE_SIM_LOCKED_OR_ABSENT:
+       case RADIO_STATE_SIM_READY:
+       case RADIO_STATE_RUIM_READY:
+       case RADIO_STATE_RUIM_LOCKED_OR_ABSENT:
+           return radioState;
+       default:
+           LOGD("decodeSimStatus: Invoked with incorrect RadioState");
+           return -1;
+   }
+}
+
+static bool is3gpp2(int radioTech) {
+    switch (radioTech) {
+        case RADIO_TECH_IS95A:
+        case RADIO_TECH_IS95B:
+        case RADIO_TECH_1xRTT:
+        case RADIO_TECH_EVDO_0:
+        case RADIO_TECH_EVDO_A:
+        case RADIO_TECH_EVDO_B:
+        case RADIO_TECH_EHRPD:
+            return true;
+        default:
+            return false;
+    }
+}
+
+/* If RIL sends SIM states or RUIM states, store the voice radio
+ * technology and subscription source information so that they can be
+ * returned when telephony framework requests them
+ */
+static RIL_RadioState
+processRadioState(RIL_RadioState newRadioState) {
+
+    if((newRadioState > RADIO_STATE_UNAVAILABLE) && (newRadioState < RADIO_STATE_ON)) {
+        int newVoiceRadioTech;
+        int newCdmaSubscriptionSource;
+        int newSimStatus;
+
+        /* This is old RIL. Decode Subscription source and Voice Radio Technology
+           from Radio State and send change notifications if there has been a change */
+        newVoiceRadioTech = decodeVoiceRadioTechnology(newRadioState);
+        if(newVoiceRadioTech != voiceRadioTech) {
+            voiceRadioTech = newVoiceRadioTech;
+            RIL_onUnsolicitedResponse (RIL_UNSOL_VOICE_RADIO_TECH_CHANGED,
+                        &voiceRadioTech, sizeof(voiceRadioTech));
+        }
+        if(is3gpp2(newVoiceRadioTech)) {
+            newCdmaSubscriptionSource = decodeCdmaSubscriptionSource(newRadioState);
+            if(newCdmaSubscriptionSource != cdmaSubscriptionSource) {
+                cdmaSubscriptionSource = newCdmaSubscriptionSource;
+                RIL_onUnsolicitedResponse (RIL_UNSOL_CDMA_SUBSCRIPTION_SOURCE_CHANGED,
+                        &cdmaSubscriptionSource, sizeof(cdmaSubscriptionSource));
+            }
+        }
+        newSimStatus = decodeSimStatus(newRadioState);
+        if(newSimStatus != simRuimStatus) {
+            simRuimStatus = newSimStatus;
+            RIL_onUnsolicitedResponse(RIL_UNSOL_RESPONSE_SIM_STATUS_CHANGED, NULL, 0);
+        }
+
+        /* Send RADIO_ON to telephony */
+        newRadioState = RADIO_STATE_ON;
+    }
+
+    return newRadioState;
+}
+
 extern "C"
 void RIL_onUnsolicitedResponse(int unsolResponse, void *data,
                                 size_t datalen)
@@ -2874,6 +3070,7 @@
     int ret;
     int64_t timeReceived = 0;
     bool shouldScheduleTimeout = false;
+    RIL_RadioState newState;
 
     if (s_registerCalled == 0) {
         // Ignore RIL_onUnsolicitedResponse before RIL_register
@@ -2930,7 +3127,8 @@
     // some things get more payload
     switch(unsolResponse) {
         case RIL_UNSOL_RESPONSE_RADIO_STATE_CHANGED:
-            p.writeInt32(s_callbacks.onStateRequest());
+            newState = processRadioState(s_callbacks.onStateRequest());
+            p.writeInt32(newState);
             appendPrintBuf("%s {%s}", printBuf,
                 radioStateToString(s_callbacks.onStateRequest()));
         break;
@@ -3062,6 +3260,7 @@
         case RADIO_STATE_RUIM_LOCKED_OR_ABSENT:return"RADIO_RUIM_LOCKED_OR_ABSENT";
         case RADIO_STATE_NV_NOT_READY:return"RADIO_NV_NOT_READY";
         case RADIO_STATE_NV_READY:return"RADIO_NV_READY";
+        case RADIO_STATE_ON:return"RADIO_ON";
         default: return "<unknown state>";
     }
 }
@@ -3196,6 +3395,7 @@
         case RIL_REQUEST_ISIM_AUTHENTICATION: return "ISIM_AUTHENTICATION";
         case RIL_REQUEST_ACKNOWLEDGE_INCOMING_GSM_SMS_WITH_PDU: return "RIL_REQUEST_ACKNOWLEDGE_INCOMING_GSM_SMS_WITH_PDU";
         case RIL_REQUEST_STK_SEND_ENVELOPE_WITH_STATUS: return "RIL_REQUEST_STK_SEND_ENVELOPE_WITH_STATUS";
+        case RIL_REQUEST_VOICE_RADIO_TECH: return "VOICE_RADIO_TECH";
         case RIL_UNSOL_RESPONSE_RADIO_STATE_CHANGED: return "UNSOL_RESPONSE_RADIO_STATE_CHANGED";
         case RIL_UNSOL_RESPONSE_CALL_STATE_CHANGED: return "UNSOL_RESPONSE_CALL_STATE_CHANGED";
         case RIL_UNSOL_RESPONSE_VOICE_NETWORK_STATE_CHANGED: return "UNSOL_RESPONSE_VOICE_NETWORK_STATE_CHANGED";
@@ -3230,6 +3430,7 @@
         case RIL_UNSOL_CDMA_PRL_CHANGED: return "UNSOL_CDMA_PRL_CHANGED";
         case RIL_UNSOL_EXIT_EMERGENCY_CALLBACK_MODE: return "UNSOL_EXIT_EMERGENCY_CALLBACK_MODE";
         case RIL_UNSOL_RIL_CONNECTED: return "UNSOL_RIL_CONNECTED";
+        case RIL_UNSOL_VOICE_RADIO_TECH_CHANGED: return "UNSOL_VOICE_RADIO_TECH_CHANGED";
         default: return "<unknown request>";
     }
 }