diff --git a/src/RpcClient/ContractClient.cs b/src/RpcClient/ContractClient.cs
index 7f340a676..18a1820f2 100644
--- a/src/RpcClient/ContractClient.cs
+++ b/src/RpcClient/ContractClient.cs
@@ -51,7 +51,7 @@ public Task<RpcInvokeResult> TestInvokeAsync(UInt160 scriptHash, string operatio
         /// <summary>
         /// Deploy Contract, return signed transaction
         /// </summary>
-        /// <param name="contractScript">contract script</param>
+        /// <param name="nefFile">neo contract executable file</param>
         /// <param name="manifest">contract manifest</param>
         /// <param name="key">sender KeyPair</param>
         /// <returns></returns>
diff --git a/src/RpcClient/Utility.cs b/src/RpcClient/Utility.cs
index fcabc7ef4..159af4046 100644
--- a/src/RpcClient/Utility.cs
+++ b/src/RpcClient/Utility.cs
@@ -69,16 +69,12 @@ public static KeyPair GetKeyPair(string key)
             if (string.IsNullOrEmpty(key)) { throw new ArgumentNullException(nameof(key)); }
             if (key.StartsWith("0x")) { key = key[2..]; }
 
-            if (key.Length == 52)
+            return key.Length switch
             {
-                return new KeyPair(Wallet.GetPrivateKeyFromWIF(key));
-            }
-            else if (key.Length == 64)
-            {
-                return new KeyPair(key.HexToBytes());
-            }
-
-            throw new FormatException();
+                52 => new KeyPair(Wallet.GetPrivateKeyFromWIF(key)),
+                64 => new KeyPair(key.HexToBytes()),
+                _ => throw new FormatException()
+            };
         }
 
         /// <summary>
@@ -86,27 +82,20 @@ public static KeyPair GetKeyPair(string key)
         /// </summary>
         /// <param name="account">account address, scripthash or public key string
         /// Example: address ("Ncm9TEzrp8SSer6Wa3UCSLTRnqzwVhCfuE"), scripthash ("0xb0a31817c80ad5f87b6ed390ecb3f9d312f7ceb8"), public key ("02f9ec1fd0a98796cf75b586772a4ddd41a0af07a1dbdf86a7238f74fb72503575")</param>
+        /// <param name="protocolSettings">The protocol settings</param>
         /// <returns></returns>
         public static UInt160 GetScriptHash(string account, ProtocolSettings protocolSettings)
         {
             if (string.IsNullOrEmpty(account)) { throw new ArgumentNullException(nameof(account)); }
             if (account.StartsWith("0x")) { account = account[2..]; }
 
-            if (account.Length == 34)
-            {
-                return Wallets.Helper.ToScriptHash(account, protocolSettings.AddressVersion);
-            }
-            else if (account.Length == 40)
-            {
-                return UInt160.Parse(account);
-            }
-            else if (account.Length == 66)
+            return account.Length switch
             {
-                var pubKey = ECPoint.Parse(account, ECCurve.Secp256r1);
-                return Contract.CreateSignatureRedeemScript(pubKey).ToScriptHash();
-            }
-
-            throw new FormatException();
+                34 => account.ToScriptHash(protocolSettings.AddressVersion),
+                40 => UInt160.Parse(account),
+                66 => Contract.CreateSignatureRedeemScript(ECPoint.Parse(account, ECCurve.Secp256r1)).ToScriptHash(),
+                _ => throw new FormatException(),
+            };
         }
 
         /// <summary>
@@ -232,29 +221,19 @@ public static WitnessRule RuleFromJson(JObject json, ProtocolSettings protocolSe
 
         public static WitnessCondition RuleExpressionFromJson(JObject json, ProtocolSettings protocolSettings)
         {
-            switch (json["type"].AsString())
+            return json["type"].AsString() switch
             {
-                case "Or":
-                    return new OrCondition() { Expressions = ((JArray)json["expressions"])?.Select(p => RuleExpressionFromJson((JObject)p, protocolSettings)).ToArray() };
-                case "And":
-                    return new AndCondition() { Expressions = ((JArray)json["expressions"])?.Select(p => RuleExpressionFromJson((JObject)p, protocolSettings)).ToArray() };
-                case "Boolean":
-                    return new BooleanCondition() { Expression = json["expression"].AsBoolean() };
-                case "Not":
-                    return new NotCondition() { Expression = RuleExpressionFromJson((JObject)json["expression"], protocolSettings) };
-                case "Group":
-                    return new GroupCondition() { Group = ECPoint.Parse(json["group"].AsString(), ECCurve.Secp256r1) };
-                case "CalledByContract":
-                    return new CalledByContractCondition() { Hash = json["hash"].ToScriptHash(protocolSettings) };
-                case "ScriptHash":
-                    return new ScriptHashCondition() { Hash = json["hash"].ToScriptHash(protocolSettings) };
-                case "CalledByEntry":
-                    return new CalledByEntryCondition();
-                case "CalledByGroup":
-                    return new CalledByGroupCondition() { Group = ECPoint.Parse(json["group"].AsString(), ECCurve.Secp256r1) };
-            }
-
-            throw new FormatException("Wrong rule's condition type");
+                "Or" => new OrCondition { Expressions = ((JArray)json["expressions"])?.Select(p => RuleExpressionFromJson((JObject)p, protocolSettings)).ToArray() },
+                "And" => new AndCondition { Expressions = ((JArray)json["expressions"])?.Select(p => RuleExpressionFromJson((JObject)p, protocolSettings)).ToArray() },
+                "Boolean" => new BooleanCondition { Expression = json["expression"].AsBoolean() },
+                "Not" => new NotCondition { Expression = RuleExpressionFromJson((JObject)json["expression"], protocolSettings) },
+                "Group" => new GroupCondition { Group = ECPoint.Parse(json["group"].AsString(), ECCurve.Secp256r1) },
+                "CalledByContract" => new CalledByContractCondition { Hash = json["hash"].ToScriptHash(protocolSettings) },
+                "ScriptHash" => new ScriptHashCondition { Hash = json["hash"].ToScriptHash(protocolSettings) },
+                "CalledByEntry" => new CalledByEntryCondition(),
+                "CalledByGroup" => new CalledByGroupCondition { Group = ECPoint.Parse(json["group"].AsString(), ECCurve.Secp256r1) },
+                _ => throw new FormatException("Wrong rule's condition type"),
+            };
         }
 
         public static StackItem StackItemFromJson(JObject json)
@@ -292,8 +271,9 @@ public static StackItem StackItemFromJson(JObject json)
                     return new Pointer(null, (int)json["value"].AsNumber());
                 case StackItemType.InteropInterface:
                     return new InteropInterface(json);
+                default:
+                    return json["value"]?.AsString() ?? StackItem.Null;
             }
-            return json["value"] is null ? StackItem.Null : json["value"].AsString();
         }
 
         public static string GetIteratorId(this StackItem item)
diff --git a/src/RpcServer/RpcServer.cs b/src/RpcServer/RpcServer.cs
index ccc581441..d28e07e57 100644
--- a/src/RpcServer/RpcServer.cs
+++ b/src/RpcServer/RpcServer.cs
@@ -15,7 +15,6 @@
 using Microsoft.AspNetCore.ResponseCompression;
 using Microsoft.AspNetCore.Server.Kestrel.Https;
 using Microsoft.Extensions.DependencyInjection;
-using Neo.IO;
 using Neo.Json;
 using Neo.Network.P2P;
 using System;