Apple iPhone 5s units will be severely constrained if all three colors (Gold, Silver, and Space Gray) people familiar with the matter told MacDailyNews.

iPhone 5s will go on sale on September 20th and long lines are expected outside Apple Retail Stores. Not all customers will get an iPhone 5s that day, our sources say.

In an email to customers today, Apple has provided details about iPhone 5s launch day:

iPhone 5s can be purchased from the Apple Online Store after 12:01am Pacific / 3:01am Eastern or via your local Apple Retail Store where sales start at 8:00am local time on September 20. Lines outside stores are expected to start forming much sooner than that.

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