As it says above. Any way to get a fix for that?

Same thing for me. This part of the code who call ClientRPC is obsolete.

Any update on that so far?

Nope, no update, I think I will create a fork for this plugin.

Same here - any alternatives out there yet?

Here is a fix

using System;
using System.Collections.Generic;
using System.Linq;
using JetBrains.Annotations;
using Newtonsoft.Json;
using Oxide.Core;
using Oxide.Core.Plugins;
using UnityEngine;
using Object = UnityEngine.Object;
using Random = Oxide.Core.Random;

namespace Oxide.Plugins
{
    [Info("Auto Lock", "birthdates", "2.4.5")]
    [Description("Automatically adds a codelock to a lockable entity with a set pin")]
    public class AutoLock : RustPlugin
    {
        #region Variables

        private const string PermissionUse = "autolock.use";
        private const string PermissionItemBypass = "autolock.item.bypass";

        private readonly Dictionary<BasePlayer, TimedCodeLock> _awaitingResponse =
            new Dictionary<BasePlayer, TimedCodeLock>();

        [UsedImplicitly] [PluginReference("NoEscape")]
        private Plugin _noEscape;

        private struct TimedCodeLock
        {
            public CodeLock CodeLock { get; set; }
            public DateTime Expiry { get; set; }
        }

        #endregion

        #region Hooks

        [UsedImplicitly]
        private void Init()
        {
            LoadConfig();
            permission.RegisterPermission(PermissionUse, this);
            permission.RegisterPermission(PermissionItemBypass, this);
            _data = Interface.Oxide.DataFileSystem.ReadObject<Data>(Name);

            cmd.AddChatCommand("autolock", this, ChatCommand);
            cmd.AddChatCommand("al", this, ChatCommand);
            if (_config.CodeLockExpiry <= 0f) Unsubscribe(nameof(OnServerInitialized));
        }

        [UsedImplicitly]
        private void OnServerInitialized()
        {
            timer.Every(3f, () =>
            {
                for (var i = _awaitingResponse.Count - 1; i > 0; i--)
                {
                    var timedLock = _awaitingResponse.ElementAt(i);
                    if (timedLock.Value.Expiry > DateTime.UtcNow) continue;
                    _awaitingResponse.Remove(timedLock.Key);
                }
            });
        }

        [UsedImplicitly]
        private void OnEntityBuilt(HeldEntity plan, GameObject go)
        {
            var player = plan.GetOwnerPlayer();
            if (player == null) return;
            if (!permission.UserHasPermission(player.UserIDString, PermissionUse)) return;

            var entity = go.ToBaseEntity() as DecayEntity;
            if (entity == null || _config.Disabled.Contains(entity.PrefabName)) return;

            var container = entity as StorageContainer;
            if (entity.IsLocked() || container != null && container.inventorySlots < 12 ||
                !container && !(entity is AnimatedBuildingBlock)) return;

            if (_noEscape != null)
            {
                if (_config.NoEscapeSettings.BlockRaid && _noEscape.Call<bool>("IsRaidBlocked", player.UserIDString))
                {
                    SendMessage(player, "RaidBlocked");
                    return;
                }

                if (_config.NoEscapeSettings.BlockCombat &&
                    _noEscape.Call<bool>("IsCombatBlocked", player.UserIDString))
                {
                    SendMessage(player, "CombatBlocked");
                    return;
                }
            }

            var playerData = CreateDataIfAbsent(player.UserIDString);
            if (!playerData.Enabled || !HasCodeLock(player)) return;

            var code = GameManager.server.CreateEntity("assets/prefabs/locks/keypad/lock.code.prefab") as CodeLock;
            if (code != null)
            {
                code.gameObject.Identity();
                code.SetParent(entity, entity.GetSlotAnchorName(BaseEntity.Slot.Lock));
                code.Spawn();
                code.code = playerData.Code;
                code.hasCode = true;
                entity.SetSlot(BaseEntity.Slot.Lock, code);
                Effect.server.Run("assets/prefabs/locks/keypad/effects/lock-code-deploy.prefab", code.transform.position);
                code.whitelistPlayers.Add(player.userID);
                code.SetFlag(BaseEntity.Flags.Locked, true);
            }

            TakeCodeLock(player);

            // Here we pass both the message key "CodeAdded" and the actual code to the SendMessage method
            SendMessage(player, "CodeAdded", playerData.Code);
        }

        private static string GetRandomCode()
        {
            return Random.Range(1000, 9999).ToString();
        }

        [UsedImplicitly]
        private void OnServerShutdown()
        {
            Unload();
        }

        private void Unload()
        {
            SaveData();
            foreach (var timedLock in _awaitingResponse.Values.Where(timedLock => !timedLock.CodeLock.IsDestroyed))
                timedLock.CodeLock.Kill();
        }

        private PlayerData CreateDataIfAbsent(string id)
        {
            PlayerData playerData;
            if (_data.Codes.TryGetValue(id, out playerData)) return playerData;
            _data.Codes.Add(id, playerData = new PlayerData
            {
                Code = GetRandomCode(),
                Enabled = true
            });
            return playerData;
        }

        #endregion

        #region Command

        private void ChatCommand(BasePlayer player, string label, string[] args)
        {
            // Check if the player has permission
            if (!permission.UserHasPermission(player.UserIDString, PermissionUse))
            {
                // Send no-permission message to the player
                SendMessage(player, "NoPermission");
                return;
            }

            // Check if the player provided enough arguments
            if (args.Length < 1)
            {
                SendMessage(player, "InvalidArgs", label);
                return;
            }

            // Ensure the player has associated data
            CreateDataIfAbsent(player.UserIDString);

            switch (args[0].ToLower())
            {
                case "code":
                    // Ensure the player has provided the code argument
                    if (args.Length != 2)
                    {
                        SendMessage(player, "InvalidArgs", label);
                        return;
                    }
                    // Set the player's code
                    SetPlayerCode(player, args[1]);
                    break;

                case "toggle":
                    // Toggle the auto-lock feature and send feedback to the player
                    SendMessage(player, Toggle(player) ? "Enabled" : "Disabled");
                    break;

                case "hide":
                    // Toggle the visibility of messages
                    ToggleHideMessages(player);
                    break;

                default:
                    // Send invalid arguments message if the command is not recognized
                    SendMessage(player, "InvalidArgs", label);
                    break;
            }
        }

        private void SendMessage(BasePlayer player, string messageKey, string code = null)
        {
            // Fetch the player's data to check if they have hidden messages
            var playerData = CreateDataIfAbsent(player.UserIDString);

            // If the player has chosen to hide messages, don't send the message
            if (playerData.HideMessages) return;

            // Fetch the localized message from the language file
            string message = lang.GetMessage(messageKey, this, player.UserIDString);

            // If a code is provided, format the message to include it
            if (code != null)
            {
                message = string.Format(message, code);
            }

            // Send the message using Rust's chat system
            player.ChatMessage(message);
        }

        private void SetPlayerCode(BasePlayer player, string code)
        {
            // Ensure the code is a 4-digit number
            if (code.Length != 4 || !int.TryParse(code, out _))
            {
                SendMessage(player, "InvalidCode");
                return;
            }

            // Find the entity the player is looking at
            RaycastHit hit;
            if (!Physics.Raycast(player.eyes.HeadRay(), out hit, 5f))
            {
                SendMessage(player, "NoEntityFound");
                return;
            }

            var entity = hit.GetEntity();
            if (entity == null)
            {
                SendMessage(player, "NoEntityFound");
                return;
            }

            // Check if the entity has a code lock
            var codeLock = entity.GetSlot(BaseEntity.Slot.Lock) as CodeLock;
            if (codeLock == null)
            {
                SendMessage(player, "NoCodeLockFound");
                return;
            }

            // Set the new code on the code lock
            codeLock.code = code;
            codeLock.hasCode = true;
            codeLock.SetFlag(BaseEntity.Flags.Locked, true);  // Ensure the lock is locked

            // Respect the player's HideMessages setting
            var playerData = CreateDataIfAbsent(player.UserIDString);
            if (!playerData.HideMessages)
            {
                // Send the message using the SendMessage method, passing the code as the second parameter
                SendMessage(player, "CodeUpdated", code);
            }

            // Play the effect to indicate the code has changed
            Effect.server.Run(codeLock.effectCodeChanged.resourcePath, codeLock.transform.position);
        }

        private void ToggleHideMessages(BasePlayer player)
        {
            var playerData = CreateDataIfAbsent(player.UserIDString);
            playerData.HideMessages = !playerData.HideMessages;

            // Inform the player whether messages are hidden or visible
            SendMessage(player, playerData.HideMessages ? "MessagesHidden" : "MessagesVisible");
        }

        private static bool HasCodeLock(BasePlayer player)
        {
            return player.IPlayer.HasPermission(PermissionItemBypass) || player.inventory.FindItemByItemID(1159991980) != null;
        }

        private static void TakeCodeLock(BasePlayer player)
        {
            if (!player.IPlayer.HasPermission(PermissionItemBypass))
                player.inventory.Take(null, 1159991980, 1);
        }

        private bool Toggle(BasePlayer player)
        {
            var data = _data.Codes[player.UserIDString];
            var newToggle = !data.Enabled;
            data.Enabled = newToggle;
            return newToggle;
        }

        #endregion

        #region Configuration & Language

        private ConfigFile _config;
        private Data _data;

        private class PlayerData
        {
            public string Code;
            public bool Enabled;
            public bool HideMessages;
        }

        private class Data
        {
            public readonly Dictionary<string, PlayerData> Codes = new Dictionary<string, PlayerData>();
        }

        protected override void LoadDefaultMessages()
        {
            lang.RegisterMessages(new Dictionary<string, string>
            {
                {"CodeAdded", "Codelock placed with code {0}."},
                {"Disabled", "You have disabled auto locks."},
                {"Enabled", "You have enabled auto locks."},
                {"CodeUpdated", "Your new code is {0}."},
                {"NoPermission", "You don't have permission."},
                {"InvalidArgs", "/{0} code|toggle|hide"},
                {"RaidBlocked", "The codelock wasn't automatically locked due to you being raid blocked!"},
                {"CombatBlocked", "The codelock wasn't automatically locked due to you being combat blocked!"},
                {"MessagesHidden", "Auto lock messages are now hidden."},
                {"MessagesVisible", "Auto lock messages are now visible."},
                {"InvalidCode", "Please enter a valid 4-digit code."},
                {"NoEntityFound", "You are not looking at a valid entity."},
                {"NoCodeLockFound", "No code lock found on the entity."}
            }, this);
        }

        public class ConfigFile
        {
            [JsonProperty("Code Lock Expiry Time (Seconds, put -1 if you want to disable)")]
            public float CodeLockExpiry;

            [JsonProperty("Disabled Items (Prefabs)")]
            public List<string> Disabled;

            [JsonProperty("No Escape")] public NoEscapeSettings NoEscapeSettings;

            public static ConfigFile DefaultConfig()
            {
                return new ConfigFile
                {
                    Disabled = new List<string>
                    {
                        "assets/prefabs/deployable/large wood storage/box.wooden.large.prefab"
                    },
                    CodeLockExpiry = 10f,
                    NoEscapeSettings = new NoEscapeSettings
                    {
                        BlockCombat = true,
                        BlockRaid = true
                    }
                };
            }
        }

        public class NoEscapeSettings
        {
            [JsonProperty("Block Auto Lock whilst in Combat?")]
            public bool BlockCombat;

            [JsonProperty("Block Auto Lock whilst Raid Blocked?")]
            public bool BlockRaid;
        }

        private void SaveData()
        {
            Interface.Oxide.DataFileSystem.WriteObject(Name, _data);
        }

        protected override void LoadConfig()
        {
            base.LoadConfig();
            _config = Config.ReadObject<ConfigFile>();
            if (_config == null) LoadDefaultConfig();
        }

        protected override void LoadDefaultConfig()
        {
            _config = ConfigFile.DefaultConfig();
            PrintWarning("Default configuration has been loaded.");
        }

        protected override void SaveConfig()
        {
            Config.WriteObject(_config);
        }

        #endregion
    }
}​

The /autlock code 1234 for example should change that code in the data file where all codes stored for the players but not the lock itself.