While today is all about Apple and its new iPhone 5S and iPhone 5C, we've noticed one little detail that may leave you questioning whether it's worth signing up for a new 24 month contract.

Remember when the Australian government auctioned off some new wireless spectrum freed up from analog TV being switched off this year?

Remember how Optus took home two lots of 10MHz (20Mhz total) in the 700MHz band and Telstra took on a heavier slice of two lots of 20MHz in the 700MHz band during the Digital Dividend?

Now, if you look carefully at the Australia iPhone 5S and 5C specs, you'll notice that the two new iPhones have some difference, but one similarity is that with both of them, the 700MHz in band 28 is not included in any of the new iPhone variants.

Which means that if Telstra and Optus switch on their 700MHz network when it becomes available in just a little over a year from now on January 1, 2015, the iPhone 5S and 5C won't actually be able to connect to it.

A 4G evolution stumble

This is not say that you won't have access to the network or 4G services at all through Optus or Telstra.

Both Telstra and Optus also use 1800MHz in spectrum bands 3 and 7 for FDD-LTE, which is supported by all iPhone 5S and 5C variants - with Apple even throwing in 4G bands compatible with Optus' multi-band TD-LTE network.

The concern lies in the fact that Telstra has plans to combine larger blocks of spectrum in the 700MHz and 1800MHz bands to enhance its new LTE-Advanced 4G network.

Meanwhile, Optus indicated that it was looking to combine the 700 MHz low-band 4G frequency for strong coverage and 2500 MHz spectrum high-band spectrum to increase network capacity after it announced the rollout of its multi-band TD-LTE network.

So while the 700MHz spectrum band is currently missing in the new line of iPhones, this doesn't mean it won't be included in next year's probable iPhone 6 launch.

But it is still a concern for those wanting a future-proof iPhone upgrade this year that will be compatible with the best of what our telcos are planning for the future of 4G networks in Australia, especially when most people will be signing up for 24 months to get their hands on the pricey phones.