diff --git a/bin/scripts/provider.lua b/bin/scripts/provider.lua
index 7f7eaaf5..de439245 100644
--- a/bin/scripts/provider.lua
+++ b/bin/scripts/provider.lua
@@ -6,6 +6,15 @@ local sys = require"sys"
 
 local persist, boot
 
+if #arg == 0 then
+  print[[
+Usage: luajit.exe scripts/provider.lua <arguments>
+Argumets:
+	persist ... Register provider, otherwise unregister
+	boot ...... Block access to network when WIPF is not running
+]]
+end
+
 -- Process arguments
 for _, v in ipairs(arg) do
   if v == "persist" then
diff --git a/src/drv/wipfdrv.c b/src/drv/wipfdrv.c
index 3dd2a3f2..adf04db5 100644
--- a/src/drv/wipfdrv.c
+++ b/src/drv/wipfdrv.c
@@ -333,7 +333,7 @@ wipf_device_control (PDEVICE_OBJECT device, PIRP irp)
     const PWIPF_CONF conf = irp->AssociatedIrp.SystemBuffer;
     const ULONG len = irp_stack->Parameters.DeviceIoControl.InputBufferLength;
 
-    if (len > WIPF_CONF_SIZE_MIN) {
+    if (len > WIPF_CONF_DATA_OFF) {
       PWIPF_CONF_REF conf_ref = wipf_conf_ref_new(conf, len);
 
       if (conf_ref == NULL) {
diff --git a/src/lua/wipflua.c b/src/lua/wipflua.c
index f34e1475..65dae670 100644
--- a/src/lua/wipflua.c
+++ b/src/lua/wipflua.c
@@ -192,7 +192,7 @@ wipf_lua_conf_buffer_size (lua_State *L)
       || apps_len > WIPF_CONF_APPS_LEN_MAX)
     return 0;
 
-  lua_pushinteger(L, WIPF_CONF_SIZE_MIN
+  lua_pushinteger(L, WIPF_CONF_DATA_OFF
       + (ip_include_n + ip_exclude_n) * 2 * sizeof(UINT32)
       + (groups_n + apps_n) * sizeof(UINT32)
       + groups_len + apps_len
@@ -267,7 +267,7 @@ wipf_lua_conf_write (lua_State *L)
   groups_off = data_offset;
   wipf_lua_conf_write_strtable(L, 18, groups_n, &data);  /* groups */
 
-  conf_size = WIPF_CONF_SIZE_MIN + data_offset;
+  conf_size = WIPF_CONF_DATA_OFF + data_offset;
 #undef data_offset
 
   conf->ip_include_all = ip_include_all;
@@ -276,6 +276,9 @@ wipf_lua_conf_write (lua_State *L)
   conf->app_block_all = app_block_all;
   conf->app_allow_all = app_allow_all;
 
+  conf->conf_version = WIPF_CONF_VERSION;
+  conf->data_off = WIPF_CONF_DATA_OFF;
+
   conf->ip_include_n = ip_include_n;
   conf->ip_exclude_n = ip_exclude_n;
 
@@ -363,7 +366,7 @@ static int
 wipf_lua_conf_read (lua_State *L)
 {
   const PWIPF_CONF conf = lua_touserdata(L, 1);
-  const char *data = (const char *) &conf->data;
+  const char *data = (const char *) conf + conf->data_off;
 
   if (!conf) return 0;
 
@@ -409,7 +412,7 @@ wipf_lua_conf_ip_inrange (lua_State *L)
   const PWIPF_CONF conf = lua_touserdata(L, 1);
   const UINT32 ip = (UINT32) lua_tonumber(L, 2);
   const BOOL included = lua_toboolean(L, 3);
-  const char *data = (const char *) &conf->data;
+  const char *data = (const char *) conf + conf->data_off;
 
   const UINT32 count = included ? conf->ip_include_n : conf->ip_exclude_n;
   const UINT32 from_off = included ? conf->ip_from_include_off : conf->ip_from_exclude_off;
diff --git a/src/wipfconf.c b/src/wipfconf.c
index 4691b86c..08aea4db 100644
--- a/src/wipfconf.c
+++ b/src/wipfconf.c
@@ -36,7 +36,7 @@ wipf_conf_ip_inrange (UINT32 ip, UINT32 count,
 static BOOL
 wipf_conf_ip_included (const PWIPF_CONF conf, UINT32 remote_ip)
 {
-  const char *data = (const char *) &conf->data;
+  const char *data = (const char *) conf + conf->data_off;
 
   const BOOL ip_included = conf->ip_include_all ? TRUE
       : wipf_conf_ip_inrange(remote_ip, conf->ip_include_n,
@@ -115,7 +115,7 @@ static BOOL
 wipf_conf_app_blocked (const PWIPF_CONF conf,
                        UINT32 path_len, const char *path, BOOL *notify)
 {
-  const char *data = (const char *) &conf->data;
+  const char *data = (const char *) conf + conf->data_off;
   const int app_index = wipf_conf_app_index(path_len, path, conf->apps_n,
       (const UINT32 *) (data + conf->apps_off));
   const UINT32 *apps_perms = (const UINT32 *) (data + conf->apps_perms_off);
diff --git a/src/wipfconf.h b/src/wipfconf.h
index 4f8d5643..7651b1fe 100644
--- a/src/wipfconf.h
+++ b/src/wipfconf.h
@@ -7,7 +7,10 @@ typedef struct wipf_conf {
   UINT32 app_log_blocked	: 1;
   UINT32 app_block_all		: 1;
   UINT32 app_allow_all		: 1;
-  UINT32 group_bits		: 10;
+  UINT32 group_bits		: 16;
+
+  UINT16 conf_version;
+  UINT16 data_off;
 
   UINT16 ip_include_n;
   UINT16 ip_exclude_n;
@@ -31,7 +34,8 @@ typedef struct wipf_conf {
   UCHAR data[4];
 } WIPF_CONF, *PWIPF_CONF;
 
-#define WIPF_CONF_SIZE_MIN		offsetof(WIPF_CONF, data)
+#define WIPF_CONF_VERSION		1
+#define WIPF_CONF_DATA_OFF		offsetof(WIPF_CONF, data)
 #define WIPF_CONF_IP_MAX		(1 * 1024 * 1024)
 #define WIPF_CONF_GROUP_MAX		16
 #define WIPF_CONF_GROUP_NAME_MAX	256
diff --git a/test/wipf_test.lua b/test/wipf_test.lua
index 817fb3fb..3453533d 100644
--- a/test/wipf_test.lua
+++ b/test/wipf_test.lua
@@ -158,8 +158,8 @@ do
   assert(not wipf.conf_ip_inrange(conf_bin, sock.inet_pton("193.0.0.0", true)))
 
   assert(wipf.conf_app_blocked(conf_bin, util_fs.path_to_dospath[[System]]))
-  assert(not wipf.conf_app_blocked(conf_bin, util_fs.path_to_dospath[[C:\Programs\Skype\Phone\Skype.exe]]))
-  assert(not wipf.conf_app_blocked(conf_bin, util_fs.path_to_dospath[[C:\Utils\Dev\Git\bin\git.exe]]))
+  assert(not wipf.conf_app_blocked(conf_bin, util_fs.path_to_dospath[[C:\programs\skype\phone\skype.exe]]))
+  assert(not wipf.conf_app_blocked(conf_bin, util_fs.path_to_dospath[[C:\utils\dev\git\bin\git.exe]]))
 
   print("OK")
 end