Hi @Deen Uthman ,
About MS AD 2012,do you mean that Windows Server 2012/2012 R2 will reach end of support on October 10, 2023?
According to my search , after this date, it will no longer receive security updates, non-security updates, bug fixes, or technical support.
For the end of support of AD operating systems, the main impact is still on-premises Exchange.
Is your organization in a hybrid deployment? Hybrid deployments have their advantages, but they also incur high costs in managing complexity.
Due to the different complexities of different organizations, you can refer to the following links to choose the way that works best for you if you are in a hybrid environment: How and when to decommission your on-premises Exchange servers in a hybrid deployment | Microsoft Learn
Of course, if you're using a purely on-premises Exchange environment, upgrading your operating system is definitely your best bet.
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