diff --git a/src/Neo.CLI/CLI/MainService.Network.cs b/src/Neo.CLI/CLI/MainService.Network.cs
index 38d6fd1d28..c579b8323e 100644
--- a/src/Neo.CLI/CLI/MainService.Network.cs
+++ b/src/Neo.CLI/CLI/MainService.Network.cs
@@ -117,7 +117,7 @@ private void OnBroadcastInvCommand(InventoryType type, UInt256[] payload)
         [ConsoleCommand("broadcast transaction", Category = "Network Commands")]
         private void OnBroadcastTransactionCommand(UInt256 hash)
         {
-            if (NeoSystem.MemPool.TryGetValue(hash, out Transaction tx))
+            if (NeoSystem.MemPool.TryGetValue(hash, out var tx))
                 OnBroadcastCommand(MessageCommand.Transaction, tx);
         }
 
diff --git a/src/Neo.CLI/CLI/MainService.Wallet.cs b/src/Neo.CLI/CLI/MainService.Wallet.cs
index db33e89564..f1390612bc 100644
--- a/src/Neo.CLI/CLI/MainService.Wallet.cs
+++ b/src/Neo.CLI/CLI/MainService.Wallet.cs
@@ -618,7 +618,7 @@ private void OnCancelCommand(UInt256 txid, UInt160? sender = null, UInt160[]? si
                 return;
             }
 
-            if (NeoSystem.MemPool.TryGetValue(txid, out Transaction conflictTx))
+            if (NeoSystem.MemPool.TryGetValue(txid, out var conflictTx))
             {
                 tx.NetworkFee = Math.Max(tx.NetworkFee, conflictTx.NetworkFee) + 1;
             }
diff --git a/src/Neo/Ledger/MemoryPool.cs b/src/Neo/Ledger/MemoryPool.cs
index ff9c6b1069..8f9437641b 100644
--- a/src/Neo/Ledger/MemoryPool.cs
+++ b/src/Neo/Ledger/MemoryPool.cs
@@ -159,7 +159,7 @@ public bool ContainsKey(UInt256 hash)
         /// <param name="hash">The hash of the <see cref="Transaction"/> to get.</param>
         /// <param name="tx">When this method returns, contains the <see cref="Transaction"/> associated with the specified hash, if the hash is found; otherwise, <see langword="null"/>.</param>
         /// <returns><see langword="true"/> if the <see cref="MemoryPool"/> contains a <see cref="Transaction"/> with the specified hash; otherwise, <see langword="false"/>.</returns>
-        public bool TryGetValue(UInt256 hash, [MaybeNullWhen(false)] out Transaction? tx)
+        public bool TryGetValue(UInt256 hash, [NotNullWhen(true)] out Transaction? tx)
         {
             _txRwLock.EnterReadLock();
             try