diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8e43d996..0d992c37 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,12 +1,17 @@
 Release History
 ===============
 
+### Version 2.1.1
+Unreleased
+
+* feat: update challenge tx helpers for SEP-0010 v1.3.0
+
 ### Version 2.1.0
 Released on January 04, 2020
 
 * feat: add support for SEP-0001 (stellar.toml).
 * feat: add support for SEP-0002 (Federation protocol).
-* perf: Adjust the client's default timeout.
+* perf: adjust the client's default timeout.
 
 ### Version 2.0.0
 Released on November 29, 2019
diff --git a/stellar_sdk/__version__.py b/stellar_sdk/__version__.py
index bba4e29a..1acabb7b 100644
--- a/stellar_sdk/__version__.py
+++ b/stellar_sdk/__version__.py
@@ -11,7 +11,7 @@
 __description__ = "The Python Stellar SDK library provides APIs to build transactions and connect to Horizon."
 __url__ = "https://github.com/StellarCN/py-stellar-base"
 __issues__ = "{}/issues".format(__url__)
-__version__ = "2.1.0"
+__version__ = "2.1.1-beta1"
 __author__ = "Eno, overcat"
 __author_email__ = "appweb.cn@gmail.com, 4catcode@gmail.com"
 __license__ = "Apache License 2.0"