diff --git a/app/scripts/util/locale.js b/app/scripts/util/locale.js
index 21920feb..1aab2367 100644
--- a/app/scripts/util/locale.js
+++ b/app/scripts/util/locale.js
@@ -121,6 +121,10 @@ var Locale = {
         'Changes you make will not be saved back to file system. ' +
         'To get the file with your data, export it from settings.',
     openLocalFileDontShow: 'Don\'t show this again',
+    openWrongFile: 'Bad file',
+    openWrongFileBody: 'This file format is not supported. This app works with KeePass database format files (KDBX).',
+    openKdbFileBody: 'You are opening an old version format file (KDB). This app supports only new format (KDBX), ' +
+        'please use KeePass v2 to convert between them.',
 
     detAttDownload: 'Shift-click attachment button to download or ',
     detAttDelToRemove: 'Delete to remove',
diff --git a/app/scripts/views/open-view.js b/app/scripts/views/open-view.js
index 243f0ea0..9bec0d90 100644
--- a/app/scripts/views/open-view.js
+++ b/app/scripts/views/open-view.js
@@ -1,6 +1,7 @@
 'use strict';
 
 var Backbone = require('backbone'),
+    kdbxweb = require('kdbxweb'),
     Keys = require('../const/keys'),
     Alerts = require('../comp/alerts'),
     SecureInput = require('../comp/secure-input'),
@@ -127,6 +128,9 @@ var OpenView = Backbone.View.extend({
         reader.onload = (function(e) {
             switch (this.reading) {
                 case 'fileData':
+                    if (!this.checkOpenFileFormat(e.target.result)) {
+                        return;
+                    }
                     this.params.id = null;
                     this.params.fileData = e.target.result;
                     this.params.name = file.name.replace(/\.\w+$/i, '');
@@ -166,6 +170,23 @@ var OpenView = Backbone.View.extend({
         }
     },
 
+    checkOpenFileFormat: function(fileData) {
+        var fileSig = new Uint32Array(fileData, 0, 2);
+        if (fileSig[0] !== kdbxweb.Consts.Signatures.FileMagic) {
+            Alerts.error({ header: Locale.openWrongFile, body: Locale.openWrongFileBody });
+            return false;
+        }
+        if (fileSig[1] === kdbxweb.Consts.Signatures.Sig2Kdb) {
+            Alerts.error({ header: Locale.openWrongFile, body: Locale.openKdbFileBody });
+            return false;
+        }
+        if (fileSig[1] !== kdbxweb.Consts.Signatures.Sig2Kdbx) {
+            Alerts.error({ header: Locale.openWrongFile, body: Locale.openWrongFileBody });
+            return false;
+        }
+        return true;
+    },
+
     displayOpenFile: function() {
         this.$el.addClass('open--file');
         this.$el.find('.open__settings-key-file').removeClass('hide');
diff --git a/bower.json b/bower.json
index f9658de4..61bf5a32 100644
--- a/bower.json
+++ b/bower.json
@@ -29,7 +29,7 @@
     "dropbox": "antelle/dropbox-js#0.10.6",
     "font-awesome": "~4.4.0",
     "install": "~1.0.4",
-    "kdbxweb": "~0.3.7",
+    "kdbxweb": "~0.3.8",
     "normalize.css": "~3.0.3",
     "pikaday": "~1.3.3",
     "FileSaver.js": "eligrey/FileSaver.js",
diff --git a/release-notes.md b/release-notes.md
index b1c17f6f..329ea0c7 100644
--- a/release-notes.md
+++ b/release-notes.md
@@ -16,6 +16,7 @@ Storage providers, usability improvements
 `+` shortcuts while the app is in background  
 `+` build for 32-bit linux  
 `+` ability to import xml  
+`+` warning for kdb files  
 `-` fix #88: capslock indicator  
 `-` fix file settings input behavior