diff --git a/CHANGELOG.md b/CHANGELOG.md
index db09e24..a597b4d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+## 2.0.0-beta.1
+
+**Bug fix:**
+
+* [socket.io-client-dart#140](https://github.com/rikulo/socket.io-client-dart/issues/140) getting Error on emitWithAck() in v2 beta
+
 ## 2.0.0-beta.0
 
 ** Features: **
diff --git a/lib/src/parser/parser.dart b/lib/src/parser/parser.dart
index 1976040..30f7cb3 100644
--- a/lib/src/parser/parser.dart
+++ b/lib/src/parser/parser.dart
@@ -224,7 +224,7 @@ class Decoder extends EventEmitter {
     if (next?.isNotEmpty == true && '${num.tryParse(next!)}' == next) {
       var start = i + 1;
       while (++i > 0) {
-        var c = str.length < i ? str[i] : null;
+        var c = str.length > i ? str[i] : null;
         if ('${num.tryParse(c!)}' != c) {
           --i;
           break;