HTC, after launching two Windows Phone devices back in 2012, when Windows Phone 8 was first released, stayed quiet for a long time. However, the company hasn't forgotten its flagship, the 8X, and have revealed that they are actively working with Microsoft to bring Windows Phone Blue to the HTC 8X. Owners of the said device who haven't moved on yet, this is the time to rejoice. Your handset hasn't been forgotten, yet.
"we're working with Microsoft on the Blue update on Windows Phone 8X and will continue to take new products into consideration." - HTC
Could HTC be working on a new WP flagship? It's possible, but at the moment, we can't confirm anything. Although, we would all love to see a 8X successor.