Update readme with 23.05 release notes

Change-Id: I4a5e1079a96ca36d3b3e1addce1f0b26508ea760
diff --git a/README.md b/README.md
index b23190c..fcedf7e 100644
--- a/README.md
+++ b/README.md
@@ -91,6 +91,19 @@
 
 Please see [Security](SECURITY.md).
 
+# Releases
+
+## Release 23.05
+
+The 23.05 release has been tested against Tensorflow version 2.11 as reference, with the additional patches applied:
+
+* https://github.com/tensorflow/tensorflow/pull/58400
+* https://github.com/tensorflow/tensorflow/pull/52014
+
+Without these patches there may be output diffs between TFL and TFLM for certain models.
+
+There's a discrepancy in tensorflow/lite/micro/cortex_m_corstone_300/README.md fixed by https://github.com/tensorflow/tflite-micro/pull/1972.
+
 # Trademark notice
 
 Arm, Cortex and Ethos are registered trademarks of Arm Limited (or its