What iPhone is coming out after the iPhone 3GS?
RH
The iPhone model that was released after the iPhone 3GS was the iPhone 4 in 2010. Here's a quick overview:
iPhone 3GS - Released in 2009, this was the third generation iPhone. It added faster processing speeds, a 3 megapixel camera, and introduced video recording capabilities.
iPhone 4 - Released in 2010 as the fourth generation iPhone. The iPhone 4 had a major redesign with a glass front and back, stainless steel edges, and introduced Retina display technology with a higher 960x640 resolution. Other new features included a 5MP camera, HD video recording, multitasking, and FaceTime video calling.
iPhone 4S - The incremental update after the iPhone 4, released in 2011. The iPhone 4S introduced Siri voice assistant capabilities, an improved 8MP camera, and faster A5 processor.
So in summary, the iPhone 4 with its completely new industrial design and several major hardware improvements was the next iPhone released after the 3GS model. The iPhone 4 represented a major leap forward for Apple's iPhone product line at the time.