diff --git a/src/format/KeePass2Reader.cpp b/src/format/KeePass2Reader.cpp
index 2a25001c..adde8cdb 100644
--- a/src/format/KeePass2Reader.cpp
+++ b/src/format/KeePass2Reader.cpp
@@ -24,6 +24,7 @@
 #include "core/Database.h"
 #include "core/Endian.h"
 #include "crypto/CryptoHash.h"
+#include "format/KeePass1.h"
 #include "format/KeePass2.h"
 #include "format/KeePass2RandomStream.h"
 #include "format/KeePass2XmlReader.h"
@@ -70,7 +71,14 @@ Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& ke
     }
 
     quint32 signature2 = Endian::readUInt32(m_headerStream, KeePass2::BYTEORDER, &ok);
-    if (!ok || signature2 != KeePass2::SIGNATURE_2) {
+    if (ok && signature2 == KeePass1::SIGNATURE_2) {
+        raiseError(tr("The selected file is an old KeePass 1 database (.kdb).\n\n"
+                      "You can import it by clicking on Database > 'Import KeePass 1 database'.\n"
+                      "This is a one-way migration. You won't be able to open the imported "
+                      "database with the old KeePassX 0.4 version."));
+        return Q_NULLPTR;
+    }
+    else if (!ok || signature2 != KeePass2::SIGNATURE_2) {
         raiseError(tr("Not a KeePass database."));
         return Q_NULLPTR;
     }