Docs: clarify downconversion of internationalized addresses

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 07b4966763dadecf4fef7c3f87106b1409ebe245..4069c29dbb5300d0f54e9773185b1dd51a65db72 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -25676,9 +25676,12 @@ operation is as if this option selected all hosts.
 .cindex utf8 "address downconversion"
 .cindex i18n "utf8 address downconversion"
 If built with internationalization support,
 .cindex utf8 "address downconversion"
 .cindex i18n "utf8 address downconversion"
 If built with internationalization support,

-this option controls conversion of UTF-8 in message addresses
+this option controls conversion of UTF-8 in message envelope addresses

 to a-label form.
 to a-label form.

-For details see section &<<SECTi18nMTA>>&.
+If, after expansion, the value is 1, 0, or -1 then this value overrides
+any value previously set for the message.  Otherwise, any previously
+set value is used.
+For details on the values see section &<<SECTi18nMTA>>&.

 
 
 
 
 
 


@@ -31097,7 +31100,7 @@ data is read.
 that are being submitted at the same time using &%-bs%& or &%-bS%&.
 
 .vitem &*control&~=&~utf8_downconvert*&
 that are being submitted at the same time using &%-bs%& or &%-bS%&.
 
 .vitem &*control&~=&~utf8_downconvert*&

-This control enables conversion of UTF-8 in message addresses
+This control enables conversion of UTF-8 in message envelope addresses

 to a-label form.
 For details see section &<<SECTi18nMTA>>&.
 .endlist vlist
 to a-label form.
 For details see section &<<SECTi18nMTA>>&.
 .endlist vlist


@@ -41524,22 +41527,27 @@ may use the following modifier:
 control = utf8_downconvert
 control = utf8_downconvert/<value>
 .endd
 control = utf8_downconvert
 control = utf8_downconvert/<value>
 .endd

-This sets a flag requiring that addresses are converted to
-a-label form before smtp delivery, for use in a
-Message Submission Agent context.
+This sets a flag requiring that envelope addresses are converted to
+a-label form before smtp delivery.
+This is usually for use in a Message Submission Agent context,
+but could be used for any message.
+

 If a value is appended it may be:
 .display
 If a value is appended it may be:
 .display

-&`1  `& (default) mandatory downconversion
+&`1  `& mandatory downconversion

 &`0  `& no downconversion
 &`-1 `& if SMTPUTF8 not supported by destination host
 .endd
 &`0  `& no downconversion
 &`-1 `& if SMTPUTF8 not supported by destination host
 .endd

+If no value is given, 1 is used.

 
 If mua_wrapper is set, the utf8_downconvert control
 is initially set to -1.
 
 The smtp transport has an option &%utf8_downconvert%&.
 If set it must expand to one of the three values described above,
 
 If mua_wrapper is set, the utf8_downconvert control
 is initially set to -1.
 
 The smtp transport has an option &%utf8_downconvert%&.
 If set it must expand to one of the three values described above,

-and it overrides any previously set value.
+or an empty string.
+If non-empty it overrides value previously set
+(due to mua_wrapper or by an ACL control).

 
 
 There is no explicit support for VRFY and EXPN.
 
 
 There is no explicit support for VRFY and EXPN.