"These problems will likely be even more complicated with a larger size"Another challenge Apple has to overcome with the 5.5-inch phone is related to the sapphire glass, rumored to be used in the company’s first phablet. While harder than glass, sapphire is still brittle and the KGI analyst does not expect it to "easily pass the drop test near term."
If Apple does not manage to overcome those issues, we’re likely to see just the 4.7” iPhone 6 this year, probably sold alongside discounted iPhone 5s and iPhone 5c.
Just last week, Kuo posted another note saying Apple is also facing manufacturing difficulties with its anticipated iWatch that might force it to release the wearable as late as in December.
Keep in mind that even though these reports are based on insider information, they are not even close to official, so it’s always useful to keep a grain of salt handy. Plus, on the 5.5” iPhone front, KGI Securities analyst Ming-Chi Kuo says there could be an optimistic outcome and - if Apple sorts all issues out - the device may still launch late this year.
source: KGI Securities via Apple Insider