Update version and spec doc

Signed-off-by: Chin Yeung Li <[email protected]>

Author: chinyeungli

SPECIFICATION.rst

@@ -173,16 +173,14 @@ URL validation, path resolution and verification, and so forth. Tools should
 report a warning for ignored fields.
 
 
-Fields order and precedence
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Fields order and multiple occurrences
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-The field order does not matter with the following exception: multiple
-occurrences of a field name are possible and must be interpreted such that only
-the last occurrence is considered as the value for this field name. Previous
-occurrences of the same field name must be treated as ignored fields.
+The field order does not matter. Multiple occurrences of a field name is not
+supported.
 
-A tool processing an ABOUT file must issue a warning when a field name occurs
-more than once in an ABOUT file (as for any other ignored field).
+The tool processing an ABOUT file or CSV/JSON input will issue an error when a
+field name occurs more than once in the input file (as for any other ignored field).
 
 
 Field referencing a file

docs/CHANGELOG.rst

@@ -1,3 +1,13 @@
+2018-x-x
+
+    Release 3.1.1
+
+    * No support of multiple occurrence keys in the input
+    * Updated the specification document
+
+    etc...
+
+
 2018-6-8  Chin-Yeung Li  <[email protected]>
 
     Release 3.1.0

src/attributecode/__init__.py

@@ -27,7 +27,7 @@
     basestring = str  # Python 3
 
 
-__version__ = '3.1.0'
+__version__ = '3.1.1'
 
 
 __about_spec_version__ = '3.0.0'