[Wallet] Ensure <0.13 clients can't open HD wallets

src/wallet/wallet.cpp

@@ -3299,6 +3299,9 @@ bool CWallet::InitLoadWallet()
             key.MakeNewKey(true);
             if (!walletInstance->SetHDMasterKey(key))
                 throw std::runtime_error("CWallet::GenerateNewKey(): Storing master key failed");
+
+            // ensure this wallet.dat can only be opened by clients supporting HD
+            walletInstance->SetMinVersion(FEATURE_HD);
         }
         CPubKey newDefaultKey;
         if (walletInstance->GetKeyFromPool(newDefaultKey)) {

src/wallet/wallet.h

@@ -78,7 +78,8 @@ enum WalletFeature
     FEATURE_WALLETCRYPT = 40000, // wallet encryption
     FEATURE_COMPRPUBKEY = 60000, // compressed public keys
 
-    FEATURE_LATEST = 60000
+    FEATURE_HD = 130000, // Hierarchical key derivation after BIP32 (HD Wallet)
+    FEATURE_LATEST = FEATURE_COMPRPUBKEY // HD is optional, use FEATURE_COMPRPUBKEY as latest version
 };