Microsoft Cloud & Security Updates | December 2025

Microsoft continues to roll out important changes across Teams Phone, Windows, and core cloud services. Below is a curated summary of the latest updates released in late 2025—what changed, why it matters, and what organizations should do to stay secure and operational.

These insights reflect Microsoft announcements and lifecycle milestones that were finalized or began rolling out throughout November 2025 and are now actively shaping customer environments heading into December.

Table of Contents

Calling Plan Licensing Changes for Auto Attendants & Call Queues

New Verification Requirement for Teams Phone (Know Your Customer – KYC)

Windows 10 & Windows Server 2016: End of Support and Extended Security Options

FAQ

Calling Plan Licensing Changes for Auto Attendants & Call Queues (Effective November 1, 2025)

Microsoft has introduced an important update that affects how outbound calls work for Teams Phone auto attendants and call queues. Beginning November 1, 2025, Calling Plan licenses assigned to resource accounts (the accounts used to power auto attendants and call queues) will no longer support outbound calls over the Public Switched Telephone Network (PSTN, the traditional phone network used for calling external numbers).

To continue making outbound calls from these systems, organizations must now assign a Pay-As-You-Go (PAYG) calling license to each resource account that initiates outbound activity.

Why This Matters

This change affects organizations that rely on Teams Phone for automated call handling, routing, or agent-assisted workflows. Without the correct license, certain outbound actions may suddenly fail — leading to dropped transfers, unsuccessful callbacks, or issues with agents placing calls on behalf of a queue.

Assigning the PAYG license ensures:

• Outbound calling continues without interruption
• Billing aligns properly with usage
• Auto attendants and call queues function as expected

Scenarios Affected

Outbound PSTN calling will require a PAYG license in the following cases:

• Agents placing outbound calls on behalf of a call queue
• Auto attendants or call queues initiating outbound calls (such as callbacks or dial-out actions)
• External transfers, where an auto attendant or queue transfers a caller to an outside phone number

If none of your resource accounts perform outbound actions, this change may not apply — but verification is still recommended.

Impact on Ascend Clients

Clients leveraging Teams Phone for call queues, auto attendants, or automated call flows should confirm licensing alignment to avoid service interruptions—especially as usage patterns shift during end-of-year operations.

Recommended Next Steps

To ensure smooth operation:

• Assign a PAYG license to any resource account that handles outbound PSTN activity
• Review call flow design to identify where outbound transfers or callbacks occur
• Check Calling Plan numbers assigned to resource accounts to confirm they have the correct license
• Contact your Ascend Microsoft team for a quick assessment or help implementing licensing updates

Source: https://learn.microsoft.com/en-us/microsoftteams/plan-auto-attendant-call-queue

New Verification Requirement for Teams Phone (Know Your Customer – KYC)

Microsoft has introduced a new identity-verification step called Know Your Customer (KYC) for any organization requesting new Teams Phone numbers. This aligns Teams Phone with standard telecom industry practices, where carriers must confirm the identity of the business before issuing public telephone numbers.

This verification occurs inside the Teams admin center and must be completed before Microsoft will release new numbers to your tenant.

Why This Matters

KYC verification helps protect organizations from fraud and unauthorized number provisioning—a growing issue across the telecom and Public Switched Telephone Network (PSTN, the traditional phone network used for external calling).

For most organizations, this adds only a small administrative step. However, if the verification is not completed ahead of time, requests for new phone numbers may be delayed.

How It Applies

For existing Teams Phone customers:

• Verification is only required when you request new phone numbers
• Any numbers you already have are not impacted

For new Teams Phone customers:

• KYC must be completed before Microsoft will issue your first set of phone numbers

Impact on Ascend Clients

If your organization is planning to:

• Add new employees
• Open or expand locations
• Build out new call queues or auto attendants
• Migrate voice services into Teams Phone

You should factor this verification step into your project timeline. Completing it proactively helps avoid bottlenecks when numbers are urgently needed. Ascend is available to guide you through the process and ensure all required documentation is ready before you submit a request.

Recommended Next Steps

• Complete business verification in the Teams admin center prior to requesting additional numbers
• Review Microsoft’s setup guide linked above
• Confirm admin contacts who can provide required documentation
• Reach out to your Ascend Microsoft team for support during verification

Source: https://learn.microsoft.com/en-us/microsoftteams/teams-phone-know-your-customer

Windows 10 & Windows Server 2016: End of Support and Extended Security Options

Microsoft has reached key lifecycle deadlines for both Windows 10 and Windows Server 2016, which affects security updates, compliance, and long-term system stability. Organizations running either operating system should begin planning for upgrades to stay protected.

Windows 10

• End of support: October 14, 2025
• Devices no longer receive security updates from Microsoft
• Security updates are only available through the Extended Security Updates (ESU) program, a paid add-on that provides temporary protection while you transition to a newer operating system

Windows Server 2016

• Mainstream support ended: January 11, 2022
• Extended support ends: January 12, 2027
• After the extended support deadline, security updates will only be available through paid ESU—similar to Windows 10

Why This Matters

• Higher security risk
• Compliance concerns (especially in regulated industries)
• Operational instability
• Increased long-term costs for maintaining outdated systems

Impact on Ascend Clients

Many organizations still rely on Windows 10 endpoints or Windows Server 2016 workloads in production. Ascend recommends beginning upgrade planning now to avoid rushed projects as deadlines approach—especially for server workloads, which often require more lead time to migrate safely.

Ascend can help assess your environment, determine which systems are affected, and build an upgrade or ESU strategy that fits your timeline and business needs.

Recommended Next Steps

• Upgrade Windows 10 devices to Windows 11 where hardware allows
• Upgrade Windows Server 2016 workloads to Windows Server 2022
• If upgrades will take time:
  • Enroll devices in the Extended Security Updates (ESU) program
  • Prioritize high-risk or externally exposed systems first
  • Review hardware readiness to ensure compatibility with newer operating systems
  • Plan a phased migration roadmap for both endpoints and servers
  • Contact your Ascend team for OS upgrade planning, server modernization guidance, or ESU procurement

Sources:
Windows 10 Support Information
https://support.microsoft.com/en-us/windows/windows-10-support-has-ended-on-october-14-2025-2ca8b313-1946-43d3-b55c-2b95b107f281

Windows Server 2016 Lifecycle
https://learn.microsoft.com/en-us/lifecycle/products/windows-server-2016

Ascend Can Help

Microsoft’s ecosystem changes fast, but you don’t have to keep up with it alone. At Ascend, we monitor these updates daily so you can stay focused on running your business—not deciphering licensing changes or security timelines. Whether you need support planning OS upgrades, validating Teams Phone licensing, or understanding how new verification or PSTN policies apply to your environment, our team is here to help.

If you have questions about any of the updates above—or want a quick review of how these changes affect your organization—reach out to your Ascend Microsoft team anytime. We’re always happy to walk through next steps with you.

FAQ

Does every resource account need a PAYG license now?

No. Only resource accounts that perform outbound PSTN calls—such as those used by auto attendants or call queues—require PAYG licensing. If the resource account only receives calls, no change is needed.

What happens if we don’t assign a PAYG license by November 1, 2025?

Outbound calls tied to that resource account will fail. Inbound calling will still work, but anything relying on outbound PSTN will stop functioning.

Do we need to complete the KYC verification process for every existing phone number?

No. Verification only applies when you request new phone numbers. All previously assigned numbers remain valid without additional steps.

How long does the Teams Phone verification (KYC) process take?

Most organizations complete verification in 1–3 business days, depending on how quickly they provide required documentation in the Teams admin center.

Do we have to upgrade all Windows 10 devices before the October 2025 deadline?

Ideally, yes. After October 14, 2025, Windows 10 stops receiving free security updates. If you need more time, purchasing the Extended Security Updates (ESU) program will keep devices protected temporarily.

What’s the risk of staying on Windows Server 2016 past January 2027?

After the extended support end date, servers will no longer receive security patches, making them vulnerable to modern threats. ESU is available, but upgrading to Windows Server 2022 is the long-term best practice.

Can Ascend help with Teams Phone licensing, OS upgrades, or ESU decisions?

Absolutely. Ascend assists with:

• Licensing reviews
• Teams Phone implementation
• Windows upgrade planning
• Server migrations
• ESU procurement and deployment
• Long-term infrastructure modernization

Just reach out—we’re here to help.