check seed_version is not too high

lib/storage.py

@@ -249,7 +249,7 @@ class WalletStorage(PrintError):
         return result
 
     def requires_upgrade(self):
-        return self.file_exists() and self.get_seed_version() != FINAL_SEED_VERSION
+        return self.file_exists() and self.get_seed_version() < FINAL_SEED_VERSION
 
     def upgrade(self):
         self.print_error('upgrading wallet format')
@@ -454,6 +454,8 @@ class WalletStorage(PrintError):
         seed_version = self.get('seed_version')
         if not seed_version:
             seed_version = OLD_SEED_VERSION if len(self.get('master_public_key','')) == 128 else NEW_SEED_VERSION
+        if seed_version > FINAL_SEED_VERSION:
+            raise BaseException('This version of Electrum is too old to open this wallet')
         if seed_version >=12:
             return seed_version
         if seed_version not in [OLD_SEED_VERSION, NEW_SEED_VERSION]: