Registered Code Stability Policy
ISO has appointed the Unicode Consortium as the Registration
Authority for International Standard 15924,
Codes for the
representation of names of scripts. Changes
to the set of registered codes must be constrained by the requirements of backward
The registration authority may
or make certain changes in codes that were previously assigned in
the registry. To minimize the impact on existing
implementations, however, there are limitations imposed by the
registration authority on the types of changes that can be made by
This document lists the policies of the Unicode Consortium
regarding registered code stability.
Once a code is assigned, it will not be reallocated, removed, or
As a result, implementers can be assured that the registry of ISO 15924
Script Codes is strictly cumulative. The registry may deprecate an assigned code (that
is, formally discourage its use), but it will not reallocate,
remove or reassign the code.
Four-letter Code and Number. Once
a code is assigned a particular four-letter mnemonic code and a
number, these will not be changed.
The numbers and four-letter codes are used to distinguish between
registered items. They are designed to be used programmatically, and thus
must be stable.
In some cases the English or French names chosen to represent the
code may be inaccurate in one way or another. Any such
inaccuracies may be dealt with by annotated changes or by adding descriptive text to the
Note: It is possible to produce translated names for
the entries in the registry, to make the information conveyed by the name
accessible to non-English and non-French speakers.