Apple’s rumored 5.5-inch “phablet” iPhone model is said to be facing issues with its new in-cell touchscreen panel as well as color unevenness on the next-gen iPhone metal casing, which could delay the device’s launch back to next year, leaving the smaller 4.70inch model to debut alone this year according to KGI Securities analyst, Ming-Chi Kuo.

According to Kuo, the Cupertino California company is already facing production bottlenecks on the 4.7-inch model related to the new technology for the device’s in-cell touch panel, as well as color unevenness on the redesigned “iPhone 6” metal casing.