X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/5407bfff21271f1c25dab2920f983beb4b1d207a..602e02546c7e38b36e4f741dad369ff46ccdea4b:/src/README.UPDATING

diff --git a/src/README.UPDATING b/src/README.UPDATING
index 3dff7c094..0d729a384 100644
--- a/src/README.UPDATING
+++ b/src/README.UPDATING
@@ -47,12 +47,36 @@ Exim version 4.78
 
    "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
 
+   COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
+   "+dont_insert_empty_fragments".  We default to unset.  That old default was
+   grandfathered in from before openssl_options became a configuration option.
+   Empty fragments are inserted by default through TLS1.0, to partially defend
+   against certain attacks; TLS1.1+ change the protocol so that this is not
+   needed.  The DIEF SSL option was required for some old releases of mail
+   clients which did not gracefully handle the empty fragments, and was
+   initially set in Exim release 4.31 (see ChangeLog, item 37).
+
+   If you still have affected mail-clients, and you see SSL protocol failures
+   with this release of Exim, set:
+     openssl_options = +dont_insert_empty_fragments
+   in the main section of your Exim configuration file.  You're trading off
+   security for compatibility.  Exim is now defaulting to higher security and
+   rewarding more modern clients.
+
  * Ldap lookups returning multi-valued attributes now separate the attributes
    with only a comma, not a comma-space sequence.  Also, an actual comma within
    a returned attribute is doubled.  This makes it possible to parse the
    attribute as a comma-separated list.  Note the distinction from multiple
    attributes being returned, where each one is a name=value pair.
 
+ * accept_8bitmime now defaults on, which is not RFC compliant but is better
+   suited to today's Internet.  See http://cr.yp.to/smtp/8bitmime.html for a
+   sane rationale.  Those who wish to be strictly RFC compliant, or know that
+   they need to talk to servers that are not 8-bit-clean, now need to take
+   explicit configuration action to default this option off.  This is not a
+   new option, you can safely force it off before upgrading, to decouple
+   configuration changes from the binary upgrade while remaining RFC compliant.
+
 
 Exim version 4.77
 -----------------