You Can Still Downgrade
It's important to know that Apple is still signing off on both the iPhone 5s iOS 9.0 update and the iPhone 5s iOS 8.4.1 update. This means that you can downgrade to either update from the iOS 9.0.1 update if the iOS 9.0.1 update is performing like you think it should performing.
We've put together a downgrade guide that will take you through the downgrade process. At the very least, we recommend getting comfortable with it just in case you need to downgrade at some point in the future.
This is a limited time deal and Apple will, at some point, stop signing off on these updates. You'll want to look into it sooner rather than later.
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