Default accept_8bitmime to true.

Some discussion at http://bugs.exim.org/show_bug.cgi?id=817

Refer readers to Dan Bernstein's analysis of the issues.
Consensus seen from maintainers is that DJB is right on this point.

4 files changed, 20 insertions, 3 deletions

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 0555672dd..2a01a1e5b 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -12850,14 +12850,23 @@ See also the &'Policy controls'& section above.
 Those options that undergo string expansion before use are marked with
 †.
 
-.option accept_8bitmime main boolean false
+.new
+.option accept_8bitmime main boolean true
 .cindex "8BITMIME"
 .cindex "8-bit characters"
 This option causes Exim to send 8BITMIME in its response to an SMTP
 EHLO command, and to accept the BODY= parameter on MAIL commands.
 However, though Exim is 8-bit clean, it is not a protocol converter, and it
 takes no steps to do anything special with messages received by this route.
-Consequently, this option is turned off by default.
+
+Historically Exim kept this option off by default, but the maintainers
+feel that in today's Internet, this causes more problems than it solves.
+It now defaults to true.
+A more detailed analysis of the issues is provided by Dan Bernstein:
+.display
+&url(http://cr.yp.to/smtp/8bitmime.html)
+.endd
+.wen
 
 .option acl_not_smtp main string&!! unset
 .cindex "&ACL;" "for non-SMTP messages"
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index e953f9b53..d202cf16b 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -89,6 +89,8 @@ PP/19 DNS resolver init changes for NetBSD compatibility.  (Risk of breakage
 PP/20 Revert part of NM/04, it broke log_path containing %D expansions.
       Left warnings.  Added "eximon gdb" invocation mode.
 
+PP/21 Defaulting "accept_8bitmime" to true, not false.
+
 
 Exim version 4.77
 -----------------
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index 2872d241f..1c8190597 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -56,6 +56,12 @@ Version 4.78
 
     Currently OpenSSL only.
 
+ 8. The existing "accept_8bitmime" option now defaults to true.  This means
+    that Exim is deliberately not strictly RFC compliant.  We're following
+    Dan Bernstein's advice in http://cr.yp.to/smtp/8bitmime.html by default.
+    Those who disagree, or know that they are talking to mail servers that,
+    even today, are not 8-bit clean, need to turn off this option.
+
 
 Version 4.77
 ------------
diff --git a/doc/doc-txt/OptionLists.txt b/doc/doc-txt/OptionLists.txt
index 52a24b198..20aeff965 100644
--- a/doc/doc-txt/OptionLists.txt
+++ b/doc/doc-txt/OptionLists.txt
@@ -48,7 +48,7 @@ release 4.00, and so no router options are shown as earlier than 4.00, though
 in fact some of them were inherited from earlier versions.
 
 -----------------------------------------------------------------------------------------
-accept_8bitmime                      boolean         false         main              1.60
+accept_8bitmime                      boolean         true          main              1.60 changed to true in 4.78
 acl_not_smtp                         string*         unset         main              4.11
 acl_not_smtp_mime                    string*         unset         main              4.51 with content scan
 acl_smtp_auth                        string*         unset         main              4.00