change fork settings to allow pre-rct txes for one more fork cycle

src/cryptonote_core/blockchain.cpp

@@ -2285,7 +2285,7 @@ bool Blockchain::check_tx_inputs(const transaction& tx, tx_verification_context
     }
 
     // for v3, we force txes with all mixable inputs to be rct
-    if (m_hardfork->get_current_version() >= 3)
+    if (m_hardfork->get_current_version() >= 4)
     {
       if (n_unmixable == 0 && tx.version == 1)
       {

src/cryptonote_core/tx_pool.cpp

@@ -85,10 +85,15 @@ namespace cryptonote
       return false;
     }
 
-    const size_t max_tx_version = version == 1 ? 1 : 2;
+    const size_t max_tx_version = (version <= 3) ? 1 : 2;
     if (tx.version > max_tx_version)
     {
-      // v2 is the latest one we know
+      tvc.m_verifivation_failed = true;
+      return false;
+    }
+    const size_t min_tx_version = (version >= 5) ? 2 : 1;
+    if (tx.version < min_tx_version)
+    {
       tvc.m_verifivation_failed = true;
       return false;
     }

src/wallet/wallet2.cpp

@@ -3254,7 +3254,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
   bool adding_fee; // true if new outputs go towards fee, rather than destinations
   uint64_t needed_fee, available_for_fee = 0;
   uint64_t upper_transaction_size_limit = get_upper_tranaction_size_limit();
-  const bool use_rct = use_fork_rules(3);
+  const bool use_rct = use_fork_rules(4);
 
   fee_multiplier = sanitize_fee_multiplier(fee_multiplier);
 
@@ -3503,7 +3503,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_all(const cryptono
   std::vector<TX> txes;
   uint64_t needed_fee, available_for_fee = 0;
   uint64_t upper_transaction_size_limit = get_upper_tranaction_size_limit();
-  const bool use_rct = use_fork_rules(3);
+  const bool use_rct = use_fork_rules(4);
 
   // gather all our dust and non dust outputs
   for (size_t i = 0; i < m_transfers.size(); ++i)