Question: Which EPUB Editing software with a GPL license was launched in February 2012 ?

text: EPUB
Software -- Editing software

EPUB is an e-book file format that uses the .epub file extension. The term is short for electronic publication and is sometimes styled ePub. EPUB is supported by many e-readers, and compatible software is available for most smartphones, tablets, and computers. EPUB is a technical standard published by the International Digital Publishing Forum (IDPF). It became an official standard of the IDPF in September 2007, superseding the older Open eBook standard. The Book Industry Study Group endorses EPUB 3 as the format of choice for packaging content and has stated that the global book publishing industry should rally around a single standard. The EPUB format is implemented as an archive file consisting of HTML files carrying the content, along with images and other supporting files. EPUB is the most widely supported vendor-independent XML-based (as opposed to PDF) e-book format; that is, it is supported by almost all hardware readers, except for Kindle.
Software Platform License Notes
ABBYY FineReader Microsoft Windows Proprietary Version 11 exports to EPUB format
Abiword FreeBSD , Linux , Windows GPL Support EPUB 2.0 format export since 2.9.1 release
Adobe InDesign Windows , OS X Proprietary Exports to EPUB format . Versions prior to 5.5 create EPUBs that require significant editing to pass ePubCheck or ePubPreFlight . As from InDesign CC 2014 , InDesign can export in ePub3 fixed-layout format
Adobe RoboHelp Windows Unknown Online documentation tool that supports export to EPUB format
Atlantis Word Processor Windows , Portable app Shareware Converts any document to EPUB ; supports multilevel TOCs , font embedding , and batch conversion
Booktype Web GPL Book production platform that outputs to many formats , including ePub . The platform can import content in various formats and supports collaborative editing
calibre Windows , OS X , FreeBSD , Linux GPL Conversion software and e-book organizer . Allows plugins , including for editing EPUB files ; there is for instance a plugin to merge several EPUB files into one
eLML Windows , OS X , FreeBSD , Linux Unknown The eLesson Markup Language is a platform-independent XML-based open source framework to create eLearning content . It supports various output formats like SCORM , HTML , PDF and also eBooks based on the ePub format
Feedbooks Web Unknown Free cloud service for downloading public domain works and for self-publishing
Help & Manual Windows Proprietary Single source publishing tool that generates ePUB amongst several other documentation formats
HelpNDoc Windows Free for personal use , commercial otherwise Help authoring tool that generates EPUB files and other formats
iBooks Author OS X Unknown Desktop publishing and page layout application . Free from Apple . Can export .ibooks format , which is a proprietary format based on EPUB . There are restrictions on the commercial distribution of works created with iBooks in the .ibooks format . These restrictions apply to the .ibooks format only and it can be argued that a file renamed to .epub is not distributed in the .ibooks format
IGP : Digital Publisher Web Proprietary Portal Cloud Service or licence application for digital content publishing to all formats . Generates ePub 2 and ePub 3 fixed and flow layout plus other formats
iStudio Publisher OS X Proprietary Desktop publishing and page layout application
LibreOffice Windows , OS X , Linux Mozilla Public License , GNU Lesser General Public License Text processor with a functionality to export as ePub3 format since version 6.0 . Also allowed to export as ePub format via installing extension , such as eLaix
Lulu.com Web Proprietary Converts .doc , .docx , or PDF manuscripts to an ePub in order that they may be sold on the Website in question
Madcap Flare Windows Proprietary Single source publishing tool that can export content as ePUB
oXygen XML Editor OS X , Windows , FreeBSD , Linux Proprietary oXygen XML Editor is the first tool that supports creating , transforming , and validating the documents that comprise the EPUB package
Pages OS X Unknown Word processor ( part of the iWork '09 suite ) that can export to EPUB format ( Pages '09 only , and only with the iWork 9.0.4 update )
Pages Apple iOS Unknown Word processor for mobile devices that can export to EPUB format