revert macOS migration

Author: xiazhvera

documents/FAQ.md

@@ -10,6 +10,7 @@
 * [How do debug in VSCode?](#how-do-debug-in-vscode)
 * [What certificates do I need?](#what-certificates-do-i-need)
 * [Where can I find MQTT 311 Samples?](#where-can-i-find-mqtt-311-samples)
+* [Certificate and Private Key Usage Across Different Versions of the SDK on macOS](#certificate-and-private-key-usage-across-different-versions-of-the-sdk-on-macos)
 * [I still have more questions about this sdk?](#i-still-have-more-questions-about-this-sdk)
 
 ### Where should I start?
@@ -154,6 +155,9 @@ Here is an example launch.json file to run the pubsub sample
 ### Where can I find MQTT 311 Samples?
 The MQTT 311 Samples can be found in the v1.24.0 samples folder [here](https://github.com/aws/aws-iot-device-sdk-python-v2/tree/v1.24.0/samples)
 
+### Certificate and Private Key Usage Across Different Versions of the SDK on macOS
+A certificate and private key pair cannot be shared on a macOS device between aws-iot-device-sdk-python-v2 v1.27.0 and any other versions. In the update to v1.27.0 we migrated macOS from using Apple's deprecated Security Framework to SecItem API. In doing so, certificate and private keys are imported in a non-backwards compatible manner into the Apple Keychain.
+
 ### I still have more questions about this sdk?
 
 * [Here](https://docs.aws.amazon.com/iot/latest/developerguide/what-is-aws-iot.html) are the AWS IoT Core docs for more details about IoT Core

setup.py

@@ -40,7 +40,7 @@ def _load_version():
         "Operating System :: OS Independent",
     ],
     install_requires=[
-        'awscrt==0.28.1',
+        'awscrt==0.31.0',
     ],
     python_requires='>=3.8',
 )