Yes it certainly looks like it has been discontinued. The product page has now been removed, and no stock from amazon.com (Seller: Amazon).
Not surprised, as I read about many issues with this light on various sites/reviews. Even after the initial release problem (Eneloops not fitting), even the newer models still had issues with switching modes. Including one of mine, one was fine, but the other only switched modes about 1/5 times correctly, never worked properly from day 1 when it arrived.
To make things worse, Surefire's "NO-HASSLE" warranty sucks. I'm overseas, and I called them but they wouldn't accept an RMA, and instead told me to contact the main dealer in Japan, so I did, but they wouldn't RMA it as I didn't purchase it through them. So I'm stuck with a non-working light.
Totally put me off of the Surefire brand, especially when they clearly lie about their ANSI specs too.
Anyway, I doubt that they'll be replacing the Titan-A, I think it's not really profitable for them, nor it is really their market. They seemed to have realized that when then scrapped their "Surefire Lifestyle" brand a few years ago, even after Andrew Wright tried selling this BS for a couple of years.