diff --git a/CHANGES.rst b/CHANGES.rst
index 40d13c6484..49dac25ca0 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,5 +1,26 @@
+Changes in synapse v0.28.1 (2018-05-01)
+=======================================
+
+SECURITY UPDATE
+
+* Clamp the allowed values of event depth received over federation to be
+  [0, 2**63 - 1].  This mitigates an attack where malicious events
+  injected with depth = 2**63 - 1 render rooms unusable.  Depth is used to
+  determine the cosmetic ordering of events within a room, and so the ordering
+  of events in such a room will default to using stream_ordering rather than depth
+  (topological_ordering).
+
+  This is a temporary solution to mitigate abuse in the wild, whilst a long solution
+  is being implemented to improve how the depth parameter is used.
+
+  Full details at
+  https://docs.google.com/document/d/1I3fi2S-XnpO45qrpCsowZv8P8dHcNZ4fsBsbOW7KABI/edit#
+
+* Pin Twisted to <18.4 until we stop using the private _OpenSSLECCurve API.
+
+
 Changes in synapse v0.28.0 (2018-04-26)
-===========================================
+=======================================
 
 Bug Fixes:
 
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 4924f44d4e..f31cb9a3cb 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -16,4 +16,4 @@
 """ This is a reference implementation of a Matrix home server.
 """
 
-__version__ = "0.28.0"
+__version__ = "0.28.1"