I'm using the Android app v1.0.51 on a HTC One with Android 4.4.3. A few weeks ago, I was able to vote to close questions - still during v1.0.51. There's no longer a vote to close option.
I have 18k reputation on this site. Yesterday, I had to open the mobile site to cast close votes.
Comments have reminded me that I can still cast close votes via flagging. This isn't the pattern the site uses, and isn't really user-friendly, evidenced by the fact I thought I had to travel to the mobile site to do this moderation.