Even if you’re not planning to upgrade your iPhone to the iPhone 5, that doesn’t mean you have to sit out the smartphone refresh fun.

Apple’s going to release the next version of its operating system, iOS 6, to the public Wednesday, which will come with an improved version of Siri, a new mapping app and calling features, such as the ability to set a “do not disturb” period.

The new system also comes with features such as shared photo streams, which will let users open up parts of their photo libraries to friends, and more Facebook integration.

In the iPhone reviews that went out today, a few reviewers had critical words for the mapping app, saying that it lacked the detail and functionality of Google Maps — the app it is replacing.

For one, Apple’s mapping feature doesn’t have built-in information about public-transit systems, said Wall Street Journal reviewer Walt Mossberg. Apple, it seems, will eventually pull in that information from other applications. For now, Engadget reviewer Tim Stevens notes, the app directs you to a currently empty search for “routing apps” when you click on an option for transportation directions.

Stevens was also underwhelmed by Passbook, the coupon and ticket app in the system, but said that he expects it will get better.

Last year, Apple released its operating system for the first time over the air, which led to server problems — both for Apple and for those who use its iCloud service.

Some of Apple’s iCloud users were hit with an outage last week that prevented users from getting their mail. That issue has since been resolved, according to Apple’s status page, but some users have reported that they’re still having problems opening the e-mails they received during the disruption, 9 to 5 Mac reported.

With luck, Apple will have smoothed out any server wrinkles and will be ready to take on the rush of eager upgraders today. According to Fortune, the company is staggering its rollout for this release.

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