i am not sure but if i remember correctly jcl or doug said that once they switch to dx10 (which probably won't happen soon!) there will be a parallel dx9 version for a while.
if you want a7 you better upgrade now. if you upgrade a5->a6 before a7 is out you will get a7 for free. afterwards you will have to do an a5->a7 upgrade which is more expensive.
