DOCX was introduced with Microsoft Word 2007, it's based on open XML and uses ZIP compression for smaller file sizes. The benefit of having open XML is that it is able to be read by applications, platforms and Internet Platforms. However to open it using any Microsoft Word that predated 2007 would require DOCX to be converted into a normal doc format.
DOCX improves file and data management and data recovery. DOCX extends what is possible with the binary files of earlier versions. Any application that supports XML can access and work with data in the new file format. The application does not need to be a Microsoft product it can be any application. Users can also use standard transformations to extract or repurpose the data. In addition, security concerns are drastically reduced because the information is stored in XML, which is essentially plain text. Thus, the data can pass through corporate firewalls without hindrance.
Microsoft Word 2007 Microsoft Word 2008 (MAC) OxygenOffice Professional (Linux) Word 2010
AZW3 - Kindle Format 8 (KF8) is Amazon's newer version of AZW. It supports HTML5 and CSS3 which were not supported through the standard AZW format. It has a number of other formatting options and is used by Amazon for all new Amazon eBooks. It is supported by fourth-generation Kindle devices running firmware version 4.1.0 or later and the Kindle Fire device.
KF8 (also called AZW3) is essentially a compiled ePub that has utlises a Palm database and Amazon's DRM scheme. It targets ePub 3 version support but existing ePub can also be used. The internal format has been decoded using mobi_unpack. The basic format remains as a PDB file similar in structure to a MOBI. More oftent than not a KF8 file will contain both a MOBI file at the beginning and the newer KF8 version of ePub later.
Kindle Fire Kindle Reader Kindle for Android Kindle for iOS