DOX and DOC are the file formats most used by Microsoft Word. We explain the differences between them, and which one you should use so that your Word documents are as compatible as possible with other applications.
The history of the move from DOC to DOCX
The DOC format was the main one in Microsoft Word until the arrival of the Word 2007 version , with which the most modern DOCX format was introduced. The DOCX format is an improved version of DOC, thereby making files smaller and less prone to corruption errors.
The DOC format began to be used more than 30 years ago with the arrival of the first version of Microsoft Word for the MS-DOS operating system. It is a proprietary format of Microsoft, which was only supported by Word. This changed in 2006 when Microsoft opened the DOC specification, making it compatible with other alternative word processors from that moment on.
The closed nature of DOC helped Microsoft dominate the office automation industry with an iron fist, as professionals were forced to pay for Microsoft Office if they wanted to be able to view their clients' files seamlessly. It was pressure from Open Office that forced Microsoft to release the DOC format , as this free proposal was increasingly popular. However, some of the more advanced DOC features were still unique to Word, so compatibility was not 100%.
The competition was pressing more and more, this made Microsoft push to adopt a more open format than DOC. It was this that caused the appearance of the DOCX format, along with its first cousins XLSX and PPTX for Excel and PowerPoint respectively. These new formats were presented under the name "Office Open XML" as they are based on the more efficient Extensible Markup Language.
DOCX is the default format for saving as a word document.
Why you should use DOCX
DOCX, XLSX, and PPTX are fully supported natively with Office versions 2007 and above , although Microsoft has added support for earlier versions. This makes them the reference formats when saving documents in the most modern versions of Microsoft Office. Its open nature allows it to be read without problems by other office applications, such as Libre Office . The only reason to continue using DOC is that you want to recover documents from many years ago, or that you have to work with very old versions of Office, something that is very unlikely to happen.