Sandra de Jenken, probably the only chair umpire with a fan base, hasn't been around much since Wimbledon. I'm told that she generally avoids the hardcourt season and shows up only for the U.S. Open, but I also hear that she has left the WTA to umpire for the ATP. Of course, she is one of the umpires with elite status that also allows her to umpire for either the ATP or the WTA in any ITF event, such as Fed Cup, Davis Cup and Grand Slam tournaments.
If de Jenken, the first woman to umpire a men's Grand Slam final, has stopped umpiring regular WTA events, it is a real loss to women's tennis. On the bright side, the move means that someone has finally noticed that a chair umpire's gender does not matter.
I tried to get a photo of de Jenken in Charleston this year but couldn't. If the news about her switch turns out to be fact, then I'll wish all the more I had gotten her picture.