Basic Authentication: End of an Era

1sep2022: Added announcement regarding Jan2023 extension

Back in September 2019, Microsoft announced it would start to turn off Basic Authentication for non-SMTP protocols in Exchange Online on tenants where the authentication protocol was detected as inactive. This is part of an overall movement to deprecate the less secure Basic Authentication, which is unfit to face the security challenges of the modern world, being subject to things like password spray attacks. It’s modern successor, modern authentication or OAuth2, uses a token and claim based mechanism contrary to sending accounts and passwords, and is the preferred authentication method. When combined with Azure AD for authentication, Modern Authentication also supports features such as Multi-Factor Authentication or Conditional Access.

The original date for disabling of Basic Authentication was October 13th, 2020. Then the world had other matters to deal with, and Microsoft extended the timelines. After initially postponing turning Basic Authentication off to second half of 2021, the ‘start date’ for permanently turning the lights off for Basic Authentication was set to October 1st, 2022, as per this article on Docs and MC286990 in the Message Center. Mind the ‘start’ in start date, as flicking the switch for millions of tenants takes time before it becomes effective on your tenant. Organizations do need to anticipate on this change for the first of October.

On September 1st, Microsoft published an update to these timelines as there were still some cases were organizations could not make the deadline of October 1st. To meet these customers “one last time”, organizations can now use the self-service diagnostics to extend disabling of Basic Authentication to January 2023. This needs to be done per protocol, also if organizations requested opt-out or re-enabled Basic Authentication earlier. Details as well as instructions and revised timelines on Basic Authentication switching off are laid out in a new article.

Until then, organizations can (re-)enable Basic Authentication for the protocols they need, using the self-help system in the Microsoft 365 admin center. After entering “Diag: Enable Basic Auth in EXO” in the problem search query, the request will be checked, and Basic Authentication will get enabled. But with the end of support for Basic Authentication, so will this temporary workaround. On a side note, per end of 2020, newly created tenants already have basic authentication disabled by means of security defaults – if those organizations require Basic Authentication for some reason, they will also need to reconfigure security defaults which by default is an all or nothing option for all protocols.

So, with the doomsday counter ticking away for Basic Authentication, what are the consequences for Exchange related workloads organizations might wonder. In this article, I will address some of these concerns.

Update: Microsoft meanwhile has disclosed much awaited details on changes in the native Mail app on iOS. This update is effective per iOS 15.6, and adds support for migrating configured accounts from using Basic Authentication to using Modern Authentication (OAuth). For this work work seamlessly and without user interruption, some configuration is needed on the back-end. Details can be found in a separate article here on this specific topic.

Click here to read the full article on ENow Solutions blog. Note that the ENow article does not include later updates, such as the latest timeline revisions and iOS account conversion, both mentioned above.

Tagging External Messages

Update 8sep2022: In Outlook v2209 build 15629.20058 C2R Beta, native External tags appeared which might remove the need to have custom forms to display those in Outlook Desktop.

Two years ago, I posted a blog on how to implement Transport Rules in Microsoft Exchange to flag messages originating from outside the organization. Goal is to aid end users in identifying messages originating from outside of the organization, by displaying tags in the subject or body part of received messages. This to make them aware – and hopefully more cautious – when it comes to clicking links or opening attachments. Downside of this method is that every inbound message gets a bit cluttered in their subject or body with tags and notifications, which becomes more evident when replying back and forth to external messages. Back then, I already stated a sort of MailTip would be a more preferable and elegant solution.

Onward to 2021, where tagging of external messages became a generally available feature in March for Exchange Online (MC243047, announcement), when used together with Outlook for Web Access (OWA), Outlook for Mac, Outlook Mobile. Outlook for Desktop will also receive support for the feature (supported per version 2105 build 14026.20000, InsiderFast currently). To start adopting this tagging mechanism for new messages, organizations need to deploy an organization level setting using Set-ExternalInOutlook, e.g.

Set-ExternalInOutlook -Enabled $True -AllowList ''

This will enable the tagging of external messages in your tenant, except for domains or e-mail addresses which have been specified through the AllowList. In the example above, messages from senders will bypass tagging. The AllowList is limited to 30 entries or 1 kB, whichever comes first. You can reconfigure the AllowList through the hashtable method, e.g.

Set-ExternalInOutlook –AllowList @{Add='',''; Remove=''}

After configuring Set-ExternalInOutlook, tagging is not immediate and can take a short while to become active. To inspect current settings, run Get-ExternalInOutlook.

How tagged mail is presented depends on the client. For example, Outlook for Web Access displays an ‘External’ label in the message list, as well as a MailTip at the top of the e-mail contents:


Same goes for Outlook Mobile, where the message list as well as the message view will show an indicator:


Outlook for Desktop
However, Outlook for Desktop does not present a label in the message list, nor exposes a field to filter those external messages, only displaying a MailTip after opening the message:


So, people almost started asking right away if it was not possible to expose External information in the message list. Well, with a little help of “Oldskool” Outlook and forms customization, this is possible, and here is how:

First, we need information related to the MAPI attribute. As the field is not by default available in Outlook, we need to know some of its properties to define it later on. As mention in some of the documents, or Glen Scales’ article on how to identify messages using Graph or Exchange Web Services, the MAPI property tag is 41F28F13-83F4-4114-A584-EEDB5A6B0BFF and its name is IsExternalSender.

Next, we need to construct a .CFG file where we will define the property we want to expose. I’ve already done this part for you, and you can download IsExternalSender.cfg from GitHub. Also download the two .ico files and put them in the same folder as the .cfg file. Note that those .ico files only represent the form. Alternatively, you can copy the .cfg file to your Personal Forms Library folder and skip installing, but this way the instruction is a bit simpler, allows you to pick the Folder Forms Library and will skip the elevated access dialog as the Personal Forms Library is a protected folder.

Open Outlook, go to File > Options > Advanced and click the Custom Forms button. There, click Manage Forms. By default, the form is installed in your Personal Folder Library. You can also pick a mailbox to store the form, allowing it to roam together with the view changes we will perform later. Click Install and pick the prepared .cfg file you downloaded from GitHub, and the following dialog should be shown:


Click OK to confirm you want to load the information in the form file in your personal forms library and close the Forms Manager. Going back to the Outlook navigation view, you can now add an IsExternalSender field to the message list. Right-click the field header and select Field Chooser. In the drop-down list, select Forms.., and add External Tagging Form to the Selected Forms. Field Chooser should now display an available field named IsExternalSender, which you can add to your current view using drag & drop.


Note that the .cfg defines the IsExternalSender as Boolean and showing it as an Icon. This means that for External messages, the column IsExternalSender will contain a checkbox:


When you want, you can create custom fields to adjust how the information is presented. For example, you can create a custom field using a formula to display [EXTERNAL] for IsExternalSender messages, which might be more usable in certain views instead of the checkbox. To accomplish this, select New in Field Chooser,and create a field named ExternalTag, type Formula and enter the following formula:


You can then add the ExternalTag field to Compact View. Do note the text takes up a row in Compact view, thus might replace sender or the subject depending on layout and field order. On a final note, when desired you can filter, sort or create Search Folders using the new IsExternalSender field.

8sep2022: In Outlook C2R Beta Channel, native tags for external messages are showing, but not (immediately) on every client, so might be part of an A/B test. The look is similar to that of Outlook Mobile:

If this feature goes GA, there’s no more need to create custom forms to have External tags showing up in Outlook for Desktop. However, there is no way to sort or filter on them, so you still might prefer that over visible-only clues.

Exchange On-Premises
Organizations running Exchange Hybrid, routing inbound messages through Exchange Online, are not able to benefit from external e-mail tagging. IsSenderExternal is only stamped on messages destined for mailboxes in Exchange Online. These organizations have therefor no way to identify these messages landing in their Exchange on-premises environment, and may require them to deploy the less elegant Transport Rules solution regardless.

Outlook Connectivity changes per Nov2021

In the past, using outdated clients with Microsoft 365 services was a matter of being in an unsupported state with all the risks that go with it. This meant, that things might not work or you could experience reduced functionality. Overall, things usually kept working with a few consequences or glitches here and there.

A change in this stance was announced today per Message Center bulletin MC229143:

To ensure that we meet performance expectations, we are updating the supported versions of Outlook for Windows that can connect to Microsoft 365 services. Effective November 1, 2021, the following versions of Outlook for Windows, as part of Office and Microsoft 365 Apps, will not be able to connect with Office 365 and Microsoft 365 services.

This means, running old unsupported Outlook versions will go from “possible performance and reliability issues” to becoming actively blocked. This block will apply to these versions in the table below; as indicated, these builds were surpassed somewhere in 2017:

ApplicationAffected BuildsBuild Superseded
Office 201315.0.4970.9999
and older
October 2017
Office 201616.0.4599.9999
and older
October 2015
Microsoft 365 Apps for Enterprise
(formerly Office 365 ProPlus)

Microsoft 365 Apps for Business
(formerly Office 365 Business

1705 and olderJune 2017

While it is true that many customers are stretching the lifetime of their on-premises products beyond their support dates, I’m sure – apart from functionality and management options – performance and reliability is becoming more and more of an issue.

Finally, when this notice concerns you, it means you have not been updating your clients for at least 3 years. So, get planning, as you have around 11 months to update your clients. It also may affect any existing plans of moving to Exchange Online in the future, as getting your client-base in a supported state will become a requirement, and will no longer be a serious recommendation.

Ignite: Outlook Calendaring Update

In the Ignite talk Outlook Calendar: Fundamentals and Collaboration, the unequaled Julia Foran laid out tons of new and coming features for the various Outlook platforms in relation to calendaring. You can watch the video on the Virtual Hub.

I tried to capture those in below table. For more information for some of these features, please watch the recording

Personal calendar side-by-side
(Hotmail/Live/MSN, Google)
Connect Shared & Delegated Mailboxes
Importing of ICS attachments🕒
Calendar To-Do pane (My Day)
Calendar To-Do pane showing Tasks (My Day)🕒
Calendar To-Do pane multiple Months support1
Suggested Times🕒🕒
Advanced Room Finder1
Room Suggestions for Recurring Meetings🕒
Room Suggestions showing Room Capabilities
(leverages Set-Place / Places REST API)
Room Suggestions and Policies integration
AllowRecurringMeeting, BookingWindowInDays, EnforceSchedulingHorizon, MaximumDurationInMinutes
Finding a Workspace
Teams meeting quick-join
In-Calendar, Inbox or Search
Online meetings by default – Outlook🕒
Built-in Breaks – End Late
Built-In Breaks – Start Late
Setting roams clients, org-wide config coming soon

Meeting Insights – Outlook
Meeting Insights – Teams


Full Mailbox Delegates
Delegates receive full calendar permissions instead of the organisation (default) permissions
Week Numbers
Setting not roaming yet
Scheduling with time zone selection
Sync local device calendars
Sync back in progress, controllable with InTune policy
Flexible Week View
Travel detection with time zone adjustment
Automatic Removal of orphaned attendees
Attendees that left company get removed from meeting after first NDR to organizer.

✔ : Already available
🕒 : Coming
⭐ : New Feature
❔ : Undetermined

1) Currently available to Office Insiders

Ignite 2019: Exchange & Related Sessions

ignite2019Note: If you are looking for the script to download Ignite contents, you can find it at the TechNet Gallery or Github.

It shouldn’t be a surprise to you, but this is the week of Ignite 2019 in Orlando, where Microsoft and other speakers will not only tell you about the latest and greatest, and how to implement recent products and use their technologies, but also draw more of the roadmap of things to come. Unfortunately, I won’t be attending Ignite (again), but similar to last year Microsoft will be live streaming keynotes, breakouts as well as theater sessions. So, you can watch stuff as it happens in the comfort of your own home or on-demand at a later time.

To access the catalog, including live streams, you can of course dive in the 1981 sessions located on the Ignite portal. Details on sessions, speakers etc. as well as filtering options are already present to help you pick what to watch, and recorded media will be added as it becomes available, including slidedecks.

For your convenience, I made a short list of sessions on Exchange Server, related technologies such as Outlook Mobile but also Teams and Groups, as well as some potentially interesting IT Pros sessions on Graph:

Session When Title Speakers
BRK2296 11/4/2019 2:15 PM Communication in Microsoft 365: Outlook and Teams integration opportunities Brandon Haist
THR2269 11/4/2019 3:00 PM Using Microsoft Teams: What’s new and how to get started Aya Tange, Jeremy Chapman
THR3039 11/4/2019 3:25 PM What’s new in the Office Customization Tool Chris Hopkins
BRK3095 11/4/2019 4:30 PM Understanding the importance of collaboration in modern work and the role O365 plays to unlock your team?s productivity Ronald Pessner, Patrick Gan, Dan Costenaro, Megan Dohnal
BRK2056 11/4/2019 4:30 PM Embrace Office 365 Groups: What’s new and what’s next Mike McLean, Venkat Ayyadevara
BRK2001 11/4/2019 4:30 PM What’s amazing and new in calendaring in Outlook Julia Foran
THR3084 11/4/2019 5:45 PM Microsoft 365 admin: Ask us anything Aaron Woo, Ben Appleby, Alice Appleton, Tim Heeney, Karissa Larson, Yeonsoo Kim
THR1131 11/4/2019 6:20 PM The solution to intranet adoption…Microsoft Teams Daniel Diefendorf
BRK3013 11/5/2019 9:00 AM Modern Exchange IT admin experiences Rahul Gupta, Eddie Savage
BRK1079 11/5/2019 10:15 AM Five hybrid cloud backup and disaster recovery mistakes to avoid Douglas Ko, Shawn Gifford, Carl Holzhauer, Julian Simpson
BRK3140 11/5/2019 10:15 AM Notes from the field: Successfully steering the government to Office 365 Michael Van Horenbeeck
BRK3012 11/5/2019 10:15 AM Exchange hybrid: Advanced scenarios, roadmap, and real-world stories! Andy Ryan, William Holmes
THR2016 11/5/2019 10:20 AM Outlook for Windows: What’s new and what’s next David Gorelik
THR3082 11/5/2019 10:55 AM Protect against phishing and other cyberthreats with Microsoft 365 Business David Bjurman-Birr
THR3083 11/5/2019 12:40 PM Office 365 Groups: Ask us anything Mike McLean, Venkat Ayyadevara, Kolvekar Loveleen Ramachandra, Nivedita Rajani, Salil Kakkar, Arunkumaran Varadharajan
THR2252 11/5/2019 1:50 PM How Microsoft manages its own employee Office 365 tenancy David Haam, David Johnson, Darren Moffatt
ADM50 11/5/2019 2:00 PM Managing across tenant boundaries in Office 365 Steve Silverberg, Robert Lowe
BRK2003 11/6/2019 9:00 AM Get ahead with Outlook mobile: Intelligent technology that helps you stay on top of your day Tali Roth, Michael Palermiti
MLS1035 11/6/2019 9:15 AM Microsoft Graph 101 for developers and IT professionals Yina Arenas, Jeremy Thake
THR3003 11/6/2019 10:55 AM New, fast, and reliable Exchange Online PowerShell cmdlets Tony Redmond
BRK3311 11/6/2019 11:30 AM Outlook mobile: The gold standard for secure communications in the enterprise Ross Smith, Lexi Torres
BRK2005 11/6/2019 12:45 PM Outlook for Mac – re-invented! Vivek Kumar, Alessio Roic
THR2270 11/6/2019 1:50 PM Microsoft Teams for IT admins: What’s new and what you need to know with Anne Michels Anne Michels, Jeremy Chapman
THR2007 11/7/2019 9:00 AM Stop organizing your own meetings ? Let Scheduler do it for you Warren Johnson
BRK3264 11/7/2019 10:15 AM Transform collaboration and fight shadow IT with Office 365 groups Arunkumaran Varadharajan, Sahil Arora
THR3033 11/7/2019 11:30 AM Reading SMTP headers like a boss Jeff Guillet
BRK2059 11/7/2019 11:30 AM Data residency with Office 365 datacenters Brian Day, Adriana Wood
THR2217 11/7/2019 12:05 PM Email is the easy part: Five pitfalls to avoid in tenant-to-tenant migrations Paul Robichaux
BRK3144 11/7/2019 1:00 PM The MVP guide to Office 365 security, Exchange Online edition Theresa Miller
BRK3142 11/7/2019 2:15 PM Things you never knew about Microsoft Teams that might be important some day Tony Redmond
BRK3312 11/7/2019 3:15 PM Office 365 email enhancements that makes your organization smart, safe, and secure Leena Sheth, Kevin Shaughnessy
BRK2104 11/7/2019 3:15 PM Your users are under attack! Strengthen your anti-phishing defense with these O365 ATP best practices Girish Chander
BRK2058 11/8/2019 9:00 AM Deploy Office 365 groups at scale to power Microsoft Teams, Outlook, Yammer, and SharePoint Salil Kakkar, Martina Grom
BRK2002 11/8/2019 9:00 AM There is a new Outlook on the web: See what’s new, fresh, and exciting David Meyers
BRK2090 11/8/2019 9:15 AM Will Microsoft Teams take over from email? Tony Redmond
BRK3248 11/8/2019 10:15 AM Securing Exchange Online from modern threats Brandon Koeller
BRK3257 11/8/2019 10:30 AM Leverage the cloud to strengthen your on-premises Active Directory security Charity Shelbourne, Mark Morowczynski
THR3034 11/8/2019 12:05 PM Twenty minutes to a secure environment Jeff Guillet

Note that the table above was constructed using the Get-EventSession script. I’ll be closely monitoring things this week to try to make sure it can retrieve Ignite contents as it gets published and cope with any changes in publishing as happened in recent years during the event.

Outlook Connection Status Details

Outlook 2016 New IconA little notice on a potential helpful feature which was introduced to Outlook at some point, but I wasn’t aware of before (or it’s just new). At least the option is available in Outlook v1905 build 11629.20008 C2R; it might also be available in standalone.

Many people are familiar with the Outlook Connection Status window, which you can summon by right-clicking the Outlook icon in the system tray while holding CTRL. This will show a dialog containing the connections Outlook is managing for every configured account, together with valuable information like endpoint, response times, etc.


One of the columns, Req/Fail, is showing the number of Requests and Failed requests. To check the headers of the last failing response for a particular connection, double-click the Req/Fail number. This will open up a popup window similar to this one:


Apart from essentials like the http result code, it will show which front-end and back-end servers processed the request. This might help to quickly determine if clients are connecting to unfavorable public endpoints, or when failed requests are coming from specific in case of Exchange on-premises. Of course, this information can also be retrieved using additional tools like Fiddler, but with this shortcut you don’t need to install additional software, as well as that you can ask end users to open up this window and send you the information.

Again, another little gem which might come in handy when troubleshooting.

Support Lifecycle changes for Office ProPlus & 2016 (a.o.)

Outlook 2013 IconIn a surprise – but welcomed – move, Microsoft announced yesterday that the office support lifecycle for Office 365 ProPlus on Windows 8.1 and Windows Server 2016 are extended to January 2023 (EOL of Windows 8.1) and October 2025 respectively. In addition, Office 2016 connectivity support for Office 365 services will be extended to October 2023 (was 2020).

Other announced changes in product support lifecycles were extending Windows 10 Enterprise & Education support from 18 to 30 months. Also, for Windows 7 Professional & Enterprise, paid security updates (Extended Security Updates) will be offered, and those Windows 7 ESU devices will be supported through January 2023 – parallel to Windows 8.1 – with Office 365 ProPlus.

The intention of these changes is to provide customers more flexibility in adopting modern desktops on the client end (i.e. Windows 10) and upgrade their Office suite, preferably to the susbscription-based ProPlus. The release cadence of the cloud has significant impact on organizations, which were told in February to keep in line with product releases as a lot of product support lifecycles were going to end in 2020.

Extending those dates not only gives them more flexibility to plan and upgrade, but also might prevent organizations to do only to the minimum, which is likely the reason many organizations are still on Windows 7 and why it took many organizations a long time to get rid of Windows XP.


Exchange 2016 & Office Online Server

pptxiconUpdate (May 9th): Office Online Server is now also available through MSDN here.

Update (May 4th): Office Online Server became available today. OOS is available on VLSC, language packs are on MSDN as well (perhaps a clue OOS will be available later on MSDN as well). Document modification option comes with additional licensing requirements, consult the release article for more information.

On April 26th, I gave a session on Exchange 2016 and Office Online Server – or OOS. Creating the session contents proved to hold some challenges. After agreeing on the session around the January timeframe, when OOS was still in Technical Preview, OOS got pulled a few weeks ago without notice. It was expected it would become Generally Available (GA) shortly after the release of SharePoint 2016, but that didn’t happen. To make matters more interesting, OOS was moved to Volume Licensing Service Center only, where its predecessor was freely available on the Microsoft download center. Currently, the status of OOS is that it is GA, and available on the VLSC site. The session and demo were based on the Technical Preview.

Back to the event, which was hosted by the always friendly and hospitable people from the Belgian E-Communications Community. At the office of Microsoft in Zaventem, Belgium, sessions were presented by 8 Microsoft MVP’s, Microsoft and sponsors, divided in 2 tracks: one Exchange-oriented track, and one track with Skype for Business related topics. Around a total of 60 people turned up in person for the event, and sessions were also  streamed live through Skype Meeting Broadcast. Excellent usage of available technology.

(picture by Michael van Horenbeeck)

After the opening keynote, Tony Redmond kicked off talking about Office 365 Groups, followed by fellow countryman Dave Stork talking about using Tools to deploy and manage Exchange. After the break, it was time for my session on Exchange 2016 and Office Online Server. Unfortunately, in the category 1st world problems, lack of an HDMI connector – required for presenting as well as streaming – on my laptop prevented me from doing the demo, and the remaining time was filled by a improvised Ask the Experts session on Exchange and Office 365, in which I was joined by the other Dutch MVP’s present. After that, Michael van Horenbeeck talked in his session about Advanced Identity & Authentication scenarios for Office 365. Jaap Wesselius closed the Exchange track with a session on the Do’s and Don’ts when using Exchange 2010 for Hybrid deployments.

The links above lead to the session recordings; a complete session overview including links to the recordings for the Skype for Business related sessions can be found here. My slidedeck – with caps of the demo – can be downloaded here. A page with links to all the slidedecks and recordings can be found here.

Knowledgebase RSS feeds

Update: Added Exchange 2016 and Skype for Business 2016 feed.

rss[1]Note: This is an update of an article from January, 2010.

Like most people I still use RSS feeds to keep track of news and updates from various sources. But did you know you can also keep track of Microsoft’s knowledgebase articles per product using RSS feeds? Great for keeping track of updates in RSS readers like Outlook or sites like Feedly, or creating triggers on sites like IFTTT (If-This-Then-That) to automatically send e-mail notifications.

Here are some RSS feeds on knowledgebase articles that might be of interest to you:

Exchange Server


Office 365

Lync/Skype for Business

For a complete list of the knowledgebase articles RSS feeds check here.

iOS 9 Outlook App & Lync 2013 App Issues

iphone6After Apple released iOS 9 to the public yesterday. From an Exchange or Office 365 perspective, iOS 9 supports the enhanced calendar features of Office 365 and Exchange 2016 when that is released. Unfortunately, incidents have been reported with the Outlook app and the Lync 2013 App.

Regarding the Outlook App, iOS9 users might not be able to start the Outlook App or the Outlook app will just crash. The far from ideal workaround offered by the Outlook team, is to reinstall the Outlook app.


Of course, this also requires users to reconfigure accounts and Outlook App settings, so organizations can expect some calls to the service desk by users who upgraded. Organizations can report on the currently registered iOS8 devices that syned in the last 30 days, using:

Get-MobileDevice | Where-Object {$_.DeviceOS -like 'iOS 8*' -and $_.whenChanged -gt (Get-Date).AddDays(-30)} | Select UserDisplayName, FriendlyName, DeviceModel, DeviceOS, whenChanged

This will product a list of users, the name of their device, the device model and OS and when it last synced with Exchange. This information can be useful when you want to proactively approach users with iOS8 devices.

For Lync 2013 users, there are sign-in issues when they have configured different region and language settings on their iOS device. Those users will be presented the following:


The issue has officially been confirmed through publication of KB3096704, which states:

“This problem is fixed in the Microsoft Skype for Business for iOS app that will replace Lync for iPhone and Lync for iPad when it’s released. No fix for this issue is scheduled for the current releases of Lync for iPhone and Lync for iPad”.

Since the Skype for Business app is not available yet, this is not good news. Mitigation is possible by matching the region with the language setting (or the other way around), after which you need to reinstall the Lync 2013 app from the store.

With all this in mind, should organizations wish to first test the new iOS against their Exchange environment for potential other issues, you can block iOS 9 from accessing your Exchange 2013 environment, or Office 365 tenant if you must, using the Access/Block/Quarantine feature. First you need to retrieve the reported DeviceOS string for iOS 9 for a device:

Get-MobileDevice | Where-Object {$_.DeviceOS -like “iOS 9*”} | Select DeviceModel, DeviceOSLanguage, DeviceOS

The reported DeviceOS strings then is used to create an ActiveSync device rule. For example, my iPhone 6 reports DeviceOS as “iOS 9.0 13A344”. To block these devices with iOS 9.0 and put them in quarantine, run the following:

New-ActiveSyncDeviceAccessRule -QueryString "iOS 9.0 13A344" -Characteristic DeviceOS -AccessLevel Quarantine

If you would like to know more about the Access/Block/Quarantine option, check out this article.