After extremely strong sales and positive reception for Apple's last flagships, the iPhone 6 and iPhone 6 Plus, it seems like the iPhone 6s and iPhone 6s Plus are well underway to becoming two of the best selling phone series of all time.

Apple's major manufacturing partners, Samsung and the Taiwan Semiconductor Manufacturing Company Limited or TSMC, are reported by DigiTimes to have both begun large-scale production of the A9 chip - which is rumored to be the follow up to the A8 chip used in previous models and will be used in the Apple iPhone 6s.

According to Digitimes, modifications were made before the mass production: "Just before production kicked off, Apple requested modifications to the mask patterns prompting both contract chipmakers to rework wafers. Nevertheless, the event should not interrupt the new iPhone launch schedule."

TSMC will also be producing fingerprint sensors and audio chips for the upcoming devices.

According to Mac Rumors, the production schedule is right on time to coincide with the rumored September of the iPhone 6s and 6s Plus. This high volume of production is expected to continue al the way into August - which would make it ready for a September release similar to the iPhone 6.

According to The Wall Street Journal, Apple has ordered and is expected to produce a record-breaking 85 to 90 million iPhone 6s and 6s Plus devices combined - which is a significant increase from the 70 to 80 million of the previous model. The strong sales of the previous model is likely to have prompted the increase in production volume.

The iPhone 6s and 6s Plus are rumored to feature a revolutionary new feature in Force Touch according to Mac Rumors. This feature, first introduced with the Apple Watch, would allow the iPhone to register the differences betwen a light tap and a hard tap. This would allow for a range of interesting gestures, motions and gaming control schemes. It is rumored that all devices from the next generation of phones will have this feature.

According to Mac Rumors, the iPhone 6s is rumored to pack an A9 processing chip, 2GB of RAM, a greatly improved 12MP camera, more precise touch identification, Force Touch and generally the same design as its predecssor.

Alongside these reports, rumors of the iPhone 6c - a smaller, cheaper alternative to Apple's flagship phones and a successor to the iPhone 5c, have also been circulating the web. The iPhone 6c is said to feature the same colorful back covers that the 5c had. It will also have a 4-inch screen and a slightly weaker A7 processing chip.