Apple could be planning on keeping its 16GB iPhone 5 handset as a mid-tier iDevice once its next-generation iPhone 5S and iPhone 5C launch, according to an internal document from Canadian carrier Telus.

The document (pictured below), which reached us from Mobile Syrup, indicates that Telus will stop selling both the 32 and 64GB iPhone 5 models from Sept. 28, 2013, but will continue offering customers the 16GB sixth-generation handset. If this is indeed the case, Apple could offer its customers three tiers of smartphone: an entry-level iPhone 5C, a mid-tier 16GB iPhone 5, and a high-end iPhone 5S.

Clearly, such a move would help the Cupertino, Calif. company better compete against Android-powered handsets, which are available at differing prices and are better equipped to capture market share in countries spanning the globe.

Here’s the document. As you can see, only Apple’s 32 and 64GB iPhone 5 handsets are to be discontinued from Sept. 28:

Telus’ internal document.

Apple is set to announce its next-generation iPhone products at a special event on Sept. 10, and the company is expected to make its new smartphones available soon after. We’ll keep you updated with further information as we receive it.

In the meantime, see: Apple Updates Its iLife Suite For iOS Ahead Of iOS 7Physics-Based Puzzle Platformer Sky Tourist Gains Mini Levels In First Update, and Google Authenticator Gets A New Look: Adds iPhone 5 And Retina Display Support.