# 1. Non-obsolescence

## CONTEXT

• Formats like XML, XLS, XML-RPC, SOAP are being deprecated by app developers in favor of JSON, XLSX, REST, OpenAPI.
• And they evolve (YAML, Graphene, etc.)
• One day, we might have something else altogether.

## DEFINITION

• Non-obsolescence is the feature of data making old formats reusable as if they were new, without transforming them to new formats.
• It has to do with representability of the functionality of old data.

## TEST CONDITIONS

• Suppose you have data like <hello>world</hello>. It is non-obsolescent, if there exists a header, that tells, how it can be understood as a functional map, so that it can be translated to other formats, like {"hello": "world"}.
• In this case, it could be a header, such as <?xml version="1.0" encoding="UTF-8"?> telling the reader how to read it.

NOTE: While file extensions were originally used to represent data formats, they proved to be insufficient as generic formats evolved. One of the primary goals for metaformat is to create such a metaheader – a universal generalized header for all I/O needs of objects (old and new) with such header.