We are currently investigating how to implement this. The expiration status is not a directory attribute so it is not straight forward how to sync it.
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There is no way for Azure AD Connect to read AccountExpired attribute correctly and below articles that describe a potential solution to this problem are wrong:
We have tested it in my company and yes, it works if you set up an expiry date for an account in the past, but will not work for accounts that have expiry date set up in the feature. This attribute will not change on the day of account expiration, hence AADC will not be able to detect a change.