sorry for the typos...
10.9 is the minimum requirement.
Thanks Bob. Any idea why I'm getting the message... "Unable to convert filename. The IDML file conversion service is temporarily unavailable. Try again later" I've tried several times, even ran it in the middle of the night. It got to 33% completed then failed again.
It is a monstrous file (162 MB) that another designer put together. Someone wants me to fix some things, but I can't open it. Ugh.
I have no idea why it's not working but yes, 162MB is pretty big for an InDesign file. How was the file sent to you?
Even packaging a CC2015 file would give you a PDF and an IDML file.
All that said, If you're going to support clients on new versions you need to keep up yourself, I'm afraid. IDML is no way to work.