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At Microsoft, we pride ourselves in providing our customers with the confidence to upgrade and update to the latest Microsoft products. Keeping up to date is crucial to minimize the risk for your customers, employees, and your business. That means helping you discover what’s possible, create a plan for success, and onboard new users and capabilities at a flexible pace.


The FastTrack App Assure service was launched in 2018 to fulfill Microsoft’s promise on application compatibility. While most apps will continue to work on Windows 10, Microsoft 365 Apps, Windows Virtual Desktop (WVD), Microsoft Edge, and Windows 10 on ARM64 PCs following deployment, App Assure engineers are available to help resolve any issues you might experience. This is part of the FastTrack benefit, which comes at no additional cost with eligible Microsoft 365 and Windows 10 plans of 150+ licenses.


Since launching, App Assure has received and evaluated nearly 750,000 applications, allowing our engineers to study and learn from customer experiences. Only a small group (approximately 0.31%) reported having any compatibility issues at all after upgrading to the latest Microsoft products, and certain questions and concerns appeared frequently. We’d like to walk through three of these commonly expressed concerns, hopefully clear up any confusion you might have, and offer some guidance based on real-world experiences over the past two years as we helped our customers resolve their application compatibility questions.


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Concern one: Staying current with Microsoft 365 will cause too many application compatibility issues

As our engineers have confirmed, staying current is important for avoiding application compatibility issues, while also ensuring devices remain protected with the latest in security updates. Planning ahead is a key to successful application compatibility, and we recommend that you define a readiness process to stay current with your Microsoft products and help identify potential issues—before you start your deployment. The tools outlined below will help you create your process.


Get started by checking out our Windows 10 deployment documentation on Docs to align to a prescriptive, process-based model for both deployment and update management that takes place across three phases: plan, prepare, and deploy. To complement this three-phase approach, there is also a step-by-step learning path to help you plan for, prepare for, and deploy updates across your organization.


Once you’ve completed the learning path and have begun your planning, follow these steps to help ensure application compatibility:

  1. Create an inventory of apps your company uses to make an informed decision about what to:

    1. Retire

    2. Keep and remediate (if necessary)

    3. Keep and modernize

  2. Microsoft 365 and Windows 10 E3 customers can use the Desktop Analytics tool to make an informed decision about the feature update readiness of your Windows clients

  3. Validate your enterprise apps to identify potential compatibility issues by utilizing these resources:

Readiness Toolkit for Office – Assesses application compatibility for Microsoft 365 applications.

Enterprise Site Discovery – Collects data and compatibility insights on devices running Internet Explorer to guide your Microsoft Edge deployment

Ready for Edge – A list of applications that your organization may be using that are supported on the newest version of Microsoft Edge


Concern two: Application code changes will always be required

Some customers described feeling reluctant to update Windows, Microsoft 365 Apps, or Microsoft Edge, as they assumed extensive discovery, triage, and mitigation efforts would be required to ensure compatibility. Specifically, changes to code were noted as a scenario our customers wished to avoid. Here, our planning comes in handy again.


By having a process to review the updates for Windows and Microsoft 365 Apps, potential problems (however unlikely) can be identified early—often before the update is applied in production—helping you minimize the risk of impact on your business.


In the rare case where code change is required to ensure that an application remains compatible, App Assure will help you resolve the issue. In most cases, there is a solution available that does not involve updating code. And if a code change is required, we will guide your team through the process. Dedicated App Assure engineers are ready to work with your developers to determine the root cause, identify any potential bugs, and make the necessary adjustments.


Concern three: My app won’t run on the latest Microsoft Edge browser

Most legacy and modern apps will work on Microsoft Edge, backed by Microsoft security and innovation and built on Chromium. Additionally, Microsoft Edge is included by default with the latest Windows 10 20H2 feature update. If your web apps or sites work in Internet Explorer 11, on supported versions of Google Chrome, or in any version of Microsoft Edge, those web apps and sites should work with Microsoft Edge. If it’s a legacy app and has ActiveX or Doc Mode dependencies, it will most likely work in the current version of Microsoft Edge by utilizing the IE mode feature along with the Enterprise Mode site list.


App Assure has helped remediate legacy apps for customers who experienced:

  • A white browser window instead of app or site content

  • Buttons missing or malfunctioning

  • Blank or inactive input fields

  • “Unsupported browser” or similar message

  • Visually misaligned content

LEARN MORE: For more Microsoft Edge deployment documentation visit here.


Still need help with your apps?

If you need help with application compatibility, please don’t hesitate to contact App Assure, which is available at no additional cost for eligible Microsoft 365 and Windows 10 plans of 150+ licenses. App Assure is part of the FastTrack for Microsoft 365 benefit, which includes remote guidance to help customers deploy Microsoft 365 products and capabilities. Visit to submit your request for assistance which will be assigned to your dedicated App Assure Manager. Learn more about App Assure compatibility assistance here. You can also watch this introductory video on App Assure.


Brought to you by Dr. Ware, Microsoft Office 365 Silver Partner, Charleston SC.