A lot of good, well established POS systems are starting to look a little long in the tooth now, and as the hackers are spending more time trying to find ways to glean your credit card info, so they banks and payment provides spend more time updating hardware and software to stop them.
Consequently, some POS are being left behind and the financial sector are no longer supporting them if they haven't updated to the latest, more secure options. According to Retail Info Systems News, many retailers are likely to be updating their POS in the next 2 years.
There are many benefits to the new POS systems, not just peace of mind for payments. A recent article in the RISN outlines some of the other advantages to improving technology.