Merge remote-tracking branch 'public/pr/1927' into development-restricted
diff --git a/ChangeLog b/ChangeLog
index 37cf750..820c26b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,19 @@
 mbed TLS ChangeLog (Sorted per branch, date)
 
+= mbed TLS 2.13.1 branch released 2018-09-06
+
+API Changes
+   * Extend the platform module with an abstraction mbedtls_platform_gmtime_r()
+     whose implementation should behave as a thread-safe version of gmtime().
+     This allows users to configure such an implementation at compile time when
+     the target system cannot be deduced automatically, by setting the option
+     MBEDTLS_PLATFORM_GMTIME_R_ALT. At this stage Mbed TLS is only able to
+     automatically select implementations for Windows and POSIX C libraries.
+
+Bugfix
+   * Fix build failures on platforms where only gmtime() is available but
+     neither gmtime_r() nor gmtime_s() are present. Fixes #1907.
+
 = mbed TLS 2.13.0 branch released 2018-08-31
 
 Security