diff --git a/lib/spdylay_frame.c b/lib/spdylay_frame.c
index 3a94e79..293375a 100644
--- a/lib/spdylay_frame.c
+++ b/lib/spdylay_frame.c
@@ -901,6 +901,10 @@ ssize_t spdylay_frame_pack_settings(uint8_t **buf_ptr, size_t *buflen_ptr,
 {
   ssize_t framelen = SPDYLAY_FRAME_HEAD_LENGTH+frame->hd.length;
   int i, r;
+  if(frame->hd.version != SPDYLAY_PROTO_SPDY2 &&
+     frame->hd.version != SPDYLAY_PROTO_SPDY3) {
+    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
+  }
   r = spdylay_reserve_buffer(buf_ptr, buflen_ptr, framelen);
   if(r != 0) {
     return r;
@@ -908,20 +912,29 @@ ssize_t spdylay_frame_pack_settings(uint8_t **buf_ptr, size_t *buflen_ptr,
   memset(*buf_ptr, 0, framelen);
   spdylay_frame_pack_ctrl_hd(*buf_ptr, &frame->hd);
   spdylay_put_uint32be(&(*buf_ptr)[8], frame->niv);
-  for(i = 0; i < frame->niv; ++i) {
-    int off = i*8;
-    /* spdy/2 spec says ID is network byte order, but publicly
-       deployed server sends little endian host byte order. */
-    char *id_ptr = (char*)(&frame->iv[i].settings_id);
+  if(frame->hd.version == SPDYLAY_PROTO_SPDY2) {
+    for(i = 0; i < frame->niv; ++i) {
+      int off = i*8;
+      /* spdy/2 spec says ID is network byte order, but publicly
+         deployed server sends little endian host byte order. */
+      char *id_ptr = (char*)(&frame->iv[i].settings_id);
 #ifdef WORDS_BIGENDIAN
-    (*buf_ptr)[12+off] = id_ptr[3];
-    (*buf_ptr)[12+off+1] = id_ptr[2];
-    (*buf_ptr)[12+off+2] = id_ptr[1];
+      (*buf_ptr)[12+off] = id_ptr[3];
+      (*buf_ptr)[12+off+1] = id_ptr[2];
+      (*buf_ptr)[12+off+2] = id_ptr[1];
 #else /* !WORDS_BIGENDIAN */
-    memcpy(&(*buf_ptr)[12+off], id_ptr, 3);
+      memcpy(&(*buf_ptr)[12+off], id_ptr, 3);
 #endif /* !WORDS_BIGENDIAN */
-    (*buf_ptr)[15+off] = frame->iv[i].flags;
-    spdylay_put_uint32be(&(*buf_ptr)[16+off], frame->iv[i].value);
+      (*buf_ptr)[15+off] = frame->iv[i].flags;
+      spdylay_put_uint32be(&(*buf_ptr)[16+off], frame->iv[i].value);
+    }
+  } else {
+    for(i = 0; i < frame->niv; ++i) {
+      int off = i*8;
+      spdylay_put_uint32be(&(*buf_ptr)[12+off], frame->iv[i].settings_id);
+      (*buf_ptr)[12+off] = frame->iv[i].flags;
+      spdylay_put_uint32be(&(*buf_ptr)[16+off], frame->iv[i].value);
+    }
   }
   return framelen;
 }
@@ -935,6 +948,10 @@ int spdylay_frame_unpack_settings(spdylay_settings *frame,
     return SPDYLAY_ERR_INVALID_FRAME;
   }
   spdylay_frame_unpack_ctrl_hd(&frame->hd, head);
+  if(frame->hd.version != SPDYLAY_PROTO_SPDY2 &&
+     frame->hd.version != SPDYLAY_PROTO_SPDY3) {
+    return SPDYLAY_ERR_UNSUPPORTED_VERSION;
+  }
   frame->niv = spdylay_get_uint32(payload);
   if(payloadlen != 4+frame->niv*8) {
     return SPDYLAY_ERR_INVALID_FRAME;
@@ -943,20 +960,30 @@ int spdylay_frame_unpack_settings(spdylay_settings *frame,
   if(frame->iv == NULL) {
     return SPDYLAY_ERR_NOMEM;
   }
-  for(i = 0; i < frame->niv; ++i) {
-    int off = i*8;
-    /* ID is little endian. See comments in
-       spdylay_frame_pack_settings(). */
-    frame->iv[i].settings_id = 0;
+  if(frame->hd.version == SPDYLAY_PROTO_SPDY2) {
+    for(i = 0; i < frame->niv; ++i) {
+      int off = i*8;
+      /* ID is little endian. See comments in
+         spdylay_frame_pack_settings(). */
+      frame->iv[i].settings_id = 0;
 #ifdef WORDS_BIGENDIAN
-    *(char*)(&frame->iv[i].settings_id[1]) = &payload[4+off+2];
-    *(char*)(&frame->iv[i].settings_id[2]) = &payload[4+off+1];
-    *(char*)(&frame->iv[i].settings_id[3]) = &payload[4+off+0];
+      *(char*)(&frame->iv[i].settings_id[1]) = &payload[4+off+2];
+      *(char*)(&frame->iv[i].settings_id[2]) = &payload[4+off+1];
+      *(char*)(&frame->iv[i].settings_id[3]) = &payload[4+off+0];
 #else /* !WORDS_BIGENDIAN */
-    memcpy(&frame->iv[i].settings_id, &payload[4+off], 3);
+      memcpy(&frame->iv[i].settings_id, &payload[4+off], 3);
 #endif /* !WORDS_BIGENDIAN */
-    frame->iv[i].flags = payload[7+off];
-    frame->iv[i].value = spdylay_get_uint32(&payload[8+off]);
+      frame->iv[i].flags = payload[7+off];
+      frame->iv[i].value = spdylay_get_uint32(&payload[8+off]);
+    }
+  } else {
+    for(i = 0; i < frame->niv; ++i) {
+      int off = i*8;
+      frame->iv[i].settings_id = spdylay_get_uint32(&payload[4+off]) &
+        SPDYLAY_SETTINGS_ID_MASK;
+      frame->iv[i].flags = payload[4+off];
+      frame->iv[i].value = spdylay_get_uint32(&payload[8+off]);
+    }
   }
   return 0;
 }
diff --git a/lib/spdylay_frame.h b/lib/spdylay_frame.h
index 1d0bde3..faa6b15 100644
--- a/lib/spdylay_frame.h
+++ b/lib/spdylay_frame.h
@@ -37,6 +37,7 @@
 #define SPDYLAY_LENGTH_MASK 0xffffff
 #define SPDYLAY_VERSION_MASK 0x7fff
 #define SPDYLAY_DELTA_WINDOW_SIZE_MASK 0x7fffffff
+#define SPDYLAY_SETTINGS_ID_MASK 0xffffff
 
 /* The length of DATA frame payload. */
 #define SPDYLAY_DATA_PAYLOAD_LENGTH 4096
@@ -353,6 +354,8 @@ int spdylay_frame_unpack_window_update(spdylay_window_update *frame,
  * This function returns the size of packed frame if it succeeds, or
  * returns one of the following negative error codes:
  *
+ * SPDYLAY_ERR_UNSUPPORTED_VERSION
+ *     The version is not supported.
  * SPDYLAY_ERR_NOMEM
  *     Out of memory.
  */
@@ -365,6 +368,8 @@ ssize_t spdylay_frame_pack_settings(uint8_t **buf_ptr, size_t *buflen_ptr,
  * This function returns 0 if it succeeds or one of the following
  * negative error codes:
  *
+ * SPDYLAY_ERR_UNSUPPORTED_VERSION
+ *     The version is not supported.
  * SPDYLAY_ERR_INVALID_FRAME
  *     The input data are invalid.
  * SPDYLAY_ERR_NOMEM
diff --git a/tests/main.c b/tests/main.c
index e87ef17..b8d5128 100644
--- a/tests/main.c
+++ b/tests/main.c
@@ -165,8 +165,10 @@ int main(int argc, char* argv[])
                    test_spdylay_frame_pack_headers_spdy3) ||
       !CU_add_test(pSuite, "frame_pack_window_update",
                    test_spdylay_frame_pack_window_update) ||
-      !CU_add_test(pSuite, "frame_pack_settings",
-                   test_spdylay_frame_pack_settings) ||
+      !CU_add_test(pSuite, "frame_pack_settings_spdy2",
+                   test_spdylay_frame_pack_settings_spdy2) ||
+      !CU_add_test(pSuite, "frame_pack_settings_spdy3",
+                   test_spdylay_frame_pack_settings_spdy3) ||
       !CU_add_test(pSuite, "frame_nv_sort", test_spdylay_frame_nv_sort) ||
       !CU_add_test(pSuite, "frame_nv_downcase",
                    test_spdylay_frame_nv_downcase) ||
diff --git a/tests/spdylay_frame_test.c b/tests/spdylay_frame_test.c
index 94ea25c..b0bc74d 100644
--- a/tests/spdylay_frame_test.c
+++ b/tests/spdylay_frame_test.c
@@ -442,7 +442,7 @@ void test_spdylay_frame_pack_window_update()
 }
 
 
-void test_spdylay_frame_pack_settings()
+void test_spdylay_frame_pack_settings_version(uint16_t version)
 {
   spdylay_frame frame, oframe;
   uint8_t *buf = NULL;
@@ -461,7 +461,7 @@ void test_spdylay_frame_pack_settings()
   iv[2].value = 65536;
 
   spdylay_frame_settings_init
-    (&frame.settings, SPDYLAY_PROTO_SPDY2,
+    (&frame.settings, version,
      SPDYLAY_FLAG_SETTINGS_CLEAR_PREVIOUSLY_PERSISTED_SETTINGS,
      spdylay_frame_iv_copy(iv, 3), 3);
   framelen = spdylay_frame_pack_settings(&buf, &buflen, &frame.settings);
@@ -473,7 +473,7 @@ void test_spdylay_frame_pack_settings()
              &buf[SPDYLAY_FRAME_HEAD_LENGTH],
              framelen-SPDYLAY_FRAME_HEAD_LENGTH));
 
-  CU_ASSERT(SPDYLAY_PROTO_SPDY2 == oframe.settings.hd.version);
+  CU_ASSERT(version == oframe.settings.hd.version);
   CU_ASSERT(SPDYLAY_SETTINGS == oframe.settings.hd.type);
   CU_ASSERT(SPDYLAY_FLAG_SETTINGS_CLEAR_PREVIOUSLY_PERSISTED_SETTINGS ==
             oframe.settings.hd.flags);
@@ -491,6 +491,16 @@ void test_spdylay_frame_pack_settings()
   spdylay_frame_settings_free(&oframe.settings);
 }
 
+void test_spdylay_frame_pack_settings_spdy2()
+{
+  test_spdylay_frame_pack_settings_version(SPDYLAY_PROTO_SPDY2);
+}
+
+void test_spdylay_frame_pack_settings_spdy3()
+{
+  test_spdylay_frame_pack_settings_version(SPDYLAY_PROTO_SPDY3);
+}
+
 void test_spdylay_frame_nv_sort()
 {
   char *nv[7];
diff --git a/tests/spdylay_frame_test.h b/tests/spdylay_frame_test.h
index 87673c3..a53aa4a 100644
--- a/tests/spdylay_frame_test.h
+++ b/tests/spdylay_frame_test.h
@@ -40,7 +40,8 @@ void test_spdylay_frame_pack_syn_reply_spdy3();
 void test_spdylay_frame_pack_headers_spdy2();
 void test_spdylay_frame_pack_headers_spdy3();
 void test_spdylay_frame_pack_window_update();
-void test_spdylay_frame_pack_settings();
+void test_spdylay_frame_pack_settings_spdy2();
+void test_spdylay_frame_pack_settings_spdy3();
 void test_spdylay_frame_nv_sort();
 void test_spdylay_frame_nv_downcase();
 void test_spdylay_frame_nv_2to3();