diff --git a/lib/lua/src/luabpack.c b/lib/lua/src/luabpack.c
index 077b6aa..cdfb72a 100644
--- a/lib/lua/src/luabpack.c
+++ b/lib/lua/src/luabpack.c
@@ -45,6 +45,7 @@
  *  c - Signed Byte
  *  s - Signed Short
  *  i - Signed Int
+ *  I - Unsigned Int
  *  l - Signed Long
  *  d - Double
  */
@@ -72,6 +73,12 @@
       luaL_addlstring(&buf, (void*)&data, sizeof(data));
       break;
     }
+    case 'I': {
+      uint32_t data = luaL_checkinteger(L, 2);
+      data = (uint32_t)htonl(data);
+      luaL_addlstring(&buf, (void*)&data, sizeof(data));
+      break;
+    }
     case 'l': {
       int64_t data = lualongnumber_checklong(L, 2);
       data = (int64_t)T_htonll(data);
@@ -97,6 +104,7 @@
  *  C - Unsigned Byte
  *  s - Signed Short
  *  i - Signed Int
+ *  I - Unsigned Int
  *  l - Signed Long
  *  d - Double
  */
@@ -144,6 +152,17 @@
       lua_pushnumber(L, val);
       break;
     }
+    /**
+     * unpack unsigned Int.
+     */
+    case 'I': {
+      uint32_t val;
+      luaL_argcheck(L, len == sizeof(val), 1, "Invalid input string size.");
+      memcpy(&val, data, sizeof(val));
+      val = (uint32_t)ntohl(val);
+      lua_pushnumber(L, val);
+      break;
+    }
     case 'l': {
       int64_t val;
       luaL_argcheck(L, len == sizeof(val), 1, "Invalid input string size.");
@@ -303,6 +322,11 @@
 };
 
 int luaopen_libluabpack(lua_State *L) {
+#if LUA_VERSION_NUM >= 502
+    lua_newtable(L);
+    luaL_setfuncs(L, lua_bpack, 0);
+#else
   luaL_register(L, "libluabpack", lua_bpack);
+#endif
   return 1;
 }