Q at 2014-09-07T21:30:22Z
"unshare option is still disabled for my older posts"
Yes, the "unshare" capability is disabled because it doesn't do what people expect, at the moment (it does "unshare", but it won't remove a shared post from your contacts' timelines).
However, if what you shared is your own note, for some reason, deleting the original note will delete the share.
Welcome back! =)