Multi-purpose Internet Mail Extensions types are media types defined by the Internet Assigned Number Authority to help programs such as your browser or mail client identify a file type and select what program to open that file with. Each file type has a single MIME type. MIME types are registered through the IANA by individual organizations via an application on the IANA website.
ODT MIME Type
The MIME type of an OpenDocument Text file is "application/vnd.oasis.opendocument.text". If you're having trouble with the MIME type, make sure that you've included the periods in the subtype. The type was registered in May 2006 and last updated in April 2009. Security considerations for the type note that ODT files can include scripts, embedded external objects and hyperlinks, and thus people opening the files of an unknown origin should use caution. There are no required parameters for the ODT type.
Other OpenDocument MIME Types
The OpenDocument format isn't reserved for just text documents; office suites like OpenOffice and LibreOffice use the OpenDocument formats as defaults for all their programs. Three OpenDocument formats include:
OpenDocument Drawing files, or ODG: "application/vnd.oasis.opendocument.graphics"
OpenDocument Spreadsheets, or ODS: "application/vnd.oasis.opendocument.spreadsheet"
OpenDocument Databases, or ODB: "application/vnd.oasis.opendocument.database".
All OpenDocument media subtypes start with "vnd.oasis.opendocument" and are listed in complete on the IANA Application types page.
The ODT MIME type was registered by Svante Schubert and OASIS, the short name for the Organization for the Advancement of Structured Information Standards. OASIS is a non-profit organization dedicated to providing worldwide open standards for technology. Schubert is affiliated with Sun Microsystems, now part of Oracle, and involved in the OpenDocument standard. The IANA provides contact information for both OASIS and Schubert if you have any questions, but the page indicates Schubert as the person to contact.
Adding ODT to .htaccess
If you're planning on embedded an ODT file on your website, you may need to add the MIME type. If your website is hosted on an Apache server but you don't have access to the server files, you can simply add the MIME types to your .htaccess file. If you don't have an .htaccess file, you can create one by creating a new file in a plain text editor. Save the file with a period at the beginning, and do not specify a file type. If it saves with the .txt extension, the file will not work when uploaded to your Web space. Once you have your .htaccess file open, simply add the following on a single line to include the ODT MIME type:
AddType application/vnd.oasis.opendocument.text .odt