Pegatron Technology has seen weakening orders from clients recently, as Apple has yet to launch its next-generation iPhones and orders for Microsoft's Surface devices have been smaller than expected, according to sources from the upstream supply chain.

Since demand for Microsoft's Surface products has been seriously undermined by other first-tier vendors' similar devices, the software giant has been conservative about placing its orders, which have been much lower than than Pegatron's original expectations, said the sources.

Although Microsoft has recently launched its inexpensive Surface Laptop, looking to regain its momentum, the device is unlikely to start boosting Pegatron's revenues until later in the third quarter of 2017, the sources said.

Meanwhile, Arima Communications has also seen weak smartphone orders from Asustek Computer, the sources said.

But the ODMs all declined to comment on matters concerning their orders and clients.

Pegatron vice chairman Jason Cheng late last month said the company expects its revenues in the second half of 2017 to at least stay flat from the same period a year ago, but it is most likely to see growth.