I'm running Indesign 2015.4 (220.127.116.11) on Windows 7 32bit. I just tried to export a fixed layout epub and it doesn't give me the option to export with the 2.1 specifications, only in epub 3.0. The final file is not rendering well in most readers. Any idea what's going on? Maybe is the 32bit version of the program? (I'm gonna try later on a Mac 64bit...)
I have also noted some other items missing in the export dialog, follows and screenshot:
Thank you for your help.
Moving to InDesign EPUB forum
Support for fixed layout epub is in 3.0 only.
Also, reader support is pretty limited right now. Try iBooks on Mac/iOS and Readium for Chrome on Windows.