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Added all of the current policy pages as of 2009/01/16.

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            <h1>About the Unicode Consortium Stability Policy</h1>

            <p>Unlike many other standards, the

            <a href="http://www.unicode.org/standard/standard.html">Unicode Standard</a> is continually 

expanding: new characters are added to meet a variety of uses, ranging from 

technical symbols to letters for archaic languages. Character properties 

are also expanded or revised to meet implementation requirements. However, 

as the Unicode Standard becomes more widely deployed, changes to the 

standard must be constrained by the requirements of  backward 

compatibility. To that end, the Unicode Consortium 

            <a href="http://www.unicode.org/policies/stability_policy.html">

            Character Encoding Stability Policy</a> <Unicode Standard> limits the ways in which the standards developed by the Unicode 

Consortium can change.</p>

<p>A primary requirement of stability is that the <i>identity</i> of the 

character remains unchanged in all future versions of the Unicode Standard. 

In other words, the same sequence of character codes continues to represent 

the same text. Consequently, character codes must never be changed, and the 

properties and behavior of a character must not change to the extent that 

it affects the identity of the character. In addition, code sequences, 

once normalized, must remain normalized.</p>



<p>Additional guarantees restricting possible changes may be added to enable 

implementers to make safe assumptions that allow more efficient and 

compact implementations. For example, by limiting the possible distinct 

values of the General Category, implementations may safely choose a packed 

format for representing them.</p>



<p>Character names are immutable, so that they can be used as constant 

external references to Unicode characters, in order to synchronize 

identifiers for characters among standards, in particular ISO standards.</p>



<p>In an ideal world, the information about existing Unicode Characters would 

be complete and correct at inception, so that maintenance of the standard 

would be purely additive. However, due to the large number of characters, 

each associated with many character properties, this ideal cannot be 

achieved. Despite best efforts, clerical errors are introduced in the 

publication process, but there are also cases where the initial information 

about a character may later prove incorrect or incomplete. In both cases, 

corrections may be required. If these can be made without implying a change 

to a character&#39;s identity, it is usually more beneficial to allow the change 

than to freeze the mistake, and the stability policy reflects that.</p>



<p>Even if a proposed correction is not prohibited by the stability policy, it 

must undergo an explicit approval process in the 

<a href="http://www.unicode.org/consortium/utc.html">Unicode Technical Committee</a>, including an analysis of its costs and benefits.</p>



In cases where the stability policy prevents a change, the UTC may take one

of several actions:

            <ul>

              <li>add additional characters with the desired properties and behavior</li>

              <li>add additional properties</li>

              <li>provide documentation of the un-modifiable mistake</li>

              <li>add a character annotation or descriptive text in the standard.</li>

            </ul>

            </p>



Occasionally, two separately encoded characters may prove to be 

unintentional duplicates of each other. In such cases, stability prevents 

removal of the duplicate character as this would impact existing data using 

it. Instead, the character may be deprecated, which retains its definition 

and properties, but strongly discourages its usage.</p>



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