Chcking for segwit activation and adding the behaviour to drop nodes when behind

Breeze/src/Breeze.Wallet/LightWalletFeature.cs

 using Stratis.Bitcoin.Builder.Feature;
 using Microsoft.Extensions.DependencyInjection;
+using NBitcoin;
+using NBitcoin.Protocol;
 using Stratis.Bitcoin.Builder;
+using Stratis.Bitcoin.Connection;
+using Stratis.Bitcoin.Consensus;
+using Stratis.Bitcoin.Consensus.Deployments;
 using Stratis.Bitcoin.Wallet;
 using Stratis.Bitcoin.Wallet.Controllers;
 
@@ -10,17 +15,30 @@ namespace Breeze.Wallet
     {
         private readonly IWalletSyncManager walletSyncManager;
         private readonly IWalletManager walletManager;
+        private readonly IConnectionManager connectionManager;
+        private readonly ConcurrentChain chain;
+        private readonly NodeDeployments nodeDeployments;
 
-        public LightWalletFeature(IWalletSyncManager walletSyncManager, IWalletManager walletManager)
+        public LightWalletFeature(IWalletSyncManager walletSyncManager, IWalletManager walletManager, IConnectionManager connectionManager, 
+            ConcurrentChain chain, NodeDeployments nodeDeployments)
         {
             this.walletSyncManager = walletSyncManager;
             this.walletManager = walletManager;
+            this.connectionManager = connectionManager;
+            this.chain = chain;
+            this.nodeDeployments = nodeDeployments;
         }
 
         public override void Start()
         {
+            this.connectionManager.Parameters.TemplateBehaviors.Add(new DropNodesBehaviour(this.chain, this.connectionManager));
+
             this.walletManager.Initialize();
             this.walletSyncManager.Initialize();
+
+            var flags = this.nodeDeployments.GetFlags(this.walletSyncManager.WalletTip);
+            if (flags.ScriptFlags.HasFlag(ScriptVerify.Witness))
+                this.connectionManager.AddDiscoveredNodesRequirement(NodeServices.NODE_WITNESS);
         }
 
         public override void Stop()
@@ -36,8 +54,8 @@ namespace Breeze.Wallet
             fullNodeBuilder.ConfigureFeature(features =>
             {
                 features
-                .AddFeature<LightWalletFeature>()
-                .FeatureServices(services =>
+                    .AddFeature<LightWalletFeature>()
+                    .FeatureServices(services =>
                     {
                         services.AddSingleton<IWalletSyncManager, LightWalletSyncManager>();
                         services.AddSingleton<IWalletManager, WalletManager>();

Breeze/src/Breeze.Wallet/LightWalletSyncManager.cs

@@ -23,6 +23,8 @@ namespace Breeze.Wallet
 
         private ChainedBlock walletTip;
 
+        public ChainedBlock WalletTip => this.walletTip;
+
         public LightWalletSyncManager(ILoggerFactory loggerFactory, IWalletManager walletManager, ConcurrentChain chain, Network network,
             BlockNotification blockNotification, Signals signals)
         {