Modifies ChangeLog and Migration Guide

Entries in ChangeLog and Migration guide files
have been merged to cover both the removal of
MBEDTLS_SSL_TRUNCATED_HMAC and
MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT.

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/ChangeLog b/ChangeLog
index ddaf3fd..b525492 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -32,8 +32,6 @@
    * Drop support for parsing SSLv2 ClientHello
      (MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO).
    * Drop support for SSLv3 (MBEDTLS_SSL_PROTO_SSL3).
-   * Drop support for compatibility with our own previous buggy
-     implementation of truncated HMAC (MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT).
    * Drop support for TLS record-level compression (MBEDTLS_ZLIB_SUPPORT).
    * Drop support for RC4 TLS ciphersuites.
    * Drop support for single-DES ciphersuites.
@@ -1688,16 +1686,6 @@
 
 = mbed TLS 2.8.0 branch released 2018-03-16
 
-Default behavior changes
-   * The truncated HMAC extension now conforms to RFC 6066. This means
-     that when both sides of a TLS connection negotiate the truncated
-     HMAC extension, Mbed TLS can now interoperate with other
-     compliant implementations, but this breaks interoperability with
-     prior versions of Mbed TLS. To restore the old behavior, enable
-     the (deprecated) option MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT in
-     config.h. Found by Andreas Walz (ivESK, Offenburg University of
-     Applied Sciences).
-
 Security
    * Fix implementation of the truncated HMAC extension. The previous
      implementation allowed an offline 2^80 brute force attack on the
diff --git a/ChangeLog.d/rm-truncated-hmac-ext.txt b/ChangeLog.d/rm-truncated-hmac-ext.txt
index c82415b..3739256 100644
--- a/ChangeLog.d/rm-truncated-hmac-ext.txt
+++ b/ChangeLog.d/rm-truncated-hmac-ext.txt
@@ -1,4 +1,5 @@
 Removals
-   * Remove MBEDTLS_SSL_TRUNCATED_HMAC config option. Users are better served by
+   * Remove MBEDTLS_SSL_TRUNCATED_HMAC and also remove
+     MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT config option. Users are better served by
      using a CCM-8 ciphersuite than a CBC ciphersuite with truncated HMAC.
-     Addresses #4341.
+     See issue #4341 for more details.
diff --git a/docs/3.0-migration-guide.d/remove-truncated-HMAC-extension.md b/docs/3.0-migration-guide.d/remove-truncated-HMAC-extension.md
deleted file mode 100644
index 12f7c23..0000000
--- a/docs/3.0-migration-guide.d/remove-truncated-HMAC-extension.md
+++ /dev/null
@@ -1,10 +0,0 @@
-Remove the truncated HMAC extension
------------------------------------
-
-This affects all users who use the truncated HMAC extension for cryptographic
-operations.
-
-The config option `MBEDTLS_SSL_TRUNCATED_HMAC` has been removed. Users concerned
-about overhead are better served by using any of the CCM-8 ciphersuites rather
-than a CBC ciphersuite with truncated HMAC, and so going forward this must be
-the approach taken.
diff --git a/docs/3.0-migration-guide.md b/docs/3.0-migration-guide.md
index a4a59b8..a30e786 100644
--- a/docs/3.0-migration-guide.md
+++ b/docs/3.0-migration-guide.md
@@ -137,17 +137,13 @@
 to date. If one of your peers is in that case, please try contacting them and
 encouraging them to upgrade their software.
 
-Remove support for compatibility with old Mbed TLS's truncated HMAC
--------------------------------------------------------------------
+Remove support for truncated HMAC
+---------------------------------
 
-This doesn't affect people using the default configuration as it was already
-disabled by default.
-
-This only affects TLS users who enabled `MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT` and
-used the Truncated HMAC extension to communicate with peers using old version
-of Mbed TLS. Please consider using a CCM-8 ciphersuite instead of the
-Truncated HMAC extension, or convincing your peer to upgrade their version of
-Mbed TLS.
+This only affects TLS users who enabled `MBEDTLS_SSL_TRUNCATED_HMAC`
+`MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT` and used the truncated HMAC extension.
+Please consider using a CCM-8 ciphersuite instead of the Truncated HMAC
+extension, or convincing your peer to upgrade their version of Mbed TLS.
 
 Remove support for TLS record-level compression
 -----------------------------------------------