dafny-4.9.0.patch

diff --git b/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/CollectionOfErrors.cs a/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/CollectionOfErrors.cs
index ef0d4752..acc77d97 100644
--- b/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/CollectionOfErrors.cs
+++ a/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/CollectionOfErrors.cs
@@ -8,9 +8,18 @@ namespace AWS.Cryptography.DbEncryptionSDK.DynamoDb.ItemEncryptor
   public class CollectionOfErrors : Exception
   {
     public readonly System.Collections.Generic.List<Exception> list;
-    public CollectionOfErrors(System.Collections.Generic.List<Exception> list, string message) : base(message) { this.list = list; }
+    public CollectionOfErrors(System.Collections.Generic.List<Exception> list, string message) : base(message + $"\n List: \n{ListAsString(list)}") { this.list = list; }
     public CollectionOfErrors(string message) : base(message) { this.list = new System.Collections.Generic.List<Exception>(); }
     public CollectionOfErrors() : base("CollectionOfErrors") { this.list = new System.Collections.Generic.List<Exception>(); }
+
+    private static string ListAsString(List<Exception> list)
+    {
+      if (list.Count < 1) return "";
+      string[] msgArr = new string[list.Count];
+      for (int i = 0; i < list.Count; i++)
+        msgArr[i] = $"{list[i].GetType().Name} :: {list[i].Message}";
+      return String.Join("\n\t", msgArr);
+    }
   }
 
 }
diff --git b/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/TypeConversion.cs a/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/TypeConversion.cs
index d1ceb19b..f96612ee 100644
--- b/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/TypeConversion.cs
+++ a/DynamoDbEncryption/runtimes/net/Generated/DynamoDbItemEncryptor/TypeConversion.cs
@@ -7,10 +7,6 @@ namespace AWS.Cryptography.DbEncryptionSDK.DynamoDb.ItemEncryptor
 {
   public static class TypeConversion
   {
-    private const string ISO8601DateFormat = "yyyy-MM-dd\\THH:mm:ss.fff\\Z";
-
-    private const string ISO8601DateFormatNoMS = "yyyy-MM-dd\\THH:mm:ss\\Z";
-
     public static AWS.Cryptography.DbEncryptionSDK.DynamoDb.ItemEncryptor.DecryptItemInput FromDafny_N3_aws__N12_cryptography__N15_dbEncryptionSdk__N8_dynamoDb__N13_itemEncryptor__S16_DecryptItemInput(software.amazon.cryptography.dbencryptionsdk.dynamodb.itemencryptor.internaldafny.types._IDecryptItemInput value)
     {
       software.amazon.cryptography.dbencryptionsdk.dynamodb.itemencryptor.internaldafny.types.DecryptItemInput concrete = (software.amazon.cryptography.dbencryptionsdk.dynamodb.itemencryptor.internaldafny.types.DecryptItemInput)value; AWS.Cryptography.DbEncryptionSDK.DynamoDb.ItemEncryptor.DecryptItemInput converted = new AWS.Cryptography.DbEncryptionSDK.DynamoDb.ItemEncryptor.DecryptItemInput(); converted.EncryptedItem = (System.Collections.Generic.Dictionary<string, Amazon.DynamoDBv2.Model.AttributeValue>)FromDafny_N3_aws__N12_cryptography__N15_dbEncryptionSdk__N8_dynamoDb__N13_itemEncryptor__S16_DecryptItemInput__M13_encryptedItem(concrete._encryptedItem); return converted;