Module Updates: What’s New?

After updating your PowerShell modules which support managing parts of the Microsoft 365, some of us are curious about what changes are introduced with the updated module. In the world of continuous change, it is hard to keep track of these changes. New cmdlets or parameters get added to support new features, and some get removed as they become obsolete. So, how to discover what those changes are after updating to the latest module?

Time to blog on a small script I created for this purpose a long time ago, Compare-Cmdlets.ps1. This script has two operating modes:

  • Export currently available cmdlets and parameters for supported modules.
  • Compare two exports of cmdlets & parameters and report the differences.

Currently, the following command sets are supported:

ModuleTest CmdletExport File
AzureADGet-AzureADUserAzureAD-<version>.xml
ExchangeOnlineGet-MailboxExchangeOnline-<version>.xml
ExchangeOnlineManagementGet-ExoMailboxExchangeOnlineManagent-<version>.xml
MicrosoftOnlineGet-MsolUserMSOnline-<version>.xml
TeamsGet-TeamMicrosoftTeams-<version>.xml

Command sets are exported per module, where a module is assumed to be present by a simple check for cmdlet availability (specified in column Test Cmdlet). That is, if Get-Mailbox is available, the ExchangeOnline module is assumed to be available. It does not distinguish between the Exchange PowerShell module or ‘classic’ Remote PowerShell session, nor will it take into account the repository origin of the module, nor if the Get-AzureADUser is coming from the AzureAD or AzureADPreview module.

That said, here’s how this is works. Load up PowerShell and have your modules installed and ready. Some modules like ExchangeOnlineManagement require connecting to the service first to import the cmdlet functions, so for ExchangeOnlineManagement run Connect-ExchangeOnline first. Same applies to the newer Teams modules, where the Skype Connector functions are only available after running New-CsOnlineSession.

Then run Compare-Cmdlets to export the cmdlets and parameters for those modules. The commands will by default be exported to an XML in a subfolder named ‘data’. The name of the file is mentioned in the table above. If you want to use a different folder to store the XML files, use DataFolder parameter.

Note that with Exchange, the cmdlets available to you depend on which role you have been assigned in Exchange’s Role-Based Access Control model. For example, if you haven’t explicitly assigned Mailbox-ImportRequest to your account, you will not see it in the exports. Therefor, when exporting module changes, it is required using an account with the same roles assigned to have proper exports. But when needed, you can also use it to report on command set differences between two Exchange Online accounts.

After updating some of the modules, or downloading one of the command set reference XMLs I stored with the script on GitHub, you can use Compare-Cmdlets to compare different versions of module exports. For example, to compare the cmdlets of Microsoft Teams module 1.1.4 with those after updating to 1.1.5, use

.\Compare-Cmdlets.ps1 -ReferenceCmds data\MicrosoftTeams-1.1.4.xml -DifferenceCmds data\MicrosoftTeams-1.1.5.xml

From the output, we see for example that:

  • The cmdlet Get-TeamChannel has a new GroupId parameter.
  • The cmdlet New-CsGroupPolicyAssignment parameter PolicyType has been removed.
  • The cmdlet Add-TeamChannelUser is new.

Note that common parameters (e.g. Verbose and ErrorAction) and optional common parameters (e.g. WhatIf) are left out of the equation. Also, parameters are not compared in depth and only presence is checked. If for example a parameter changes type (e.g. string to multivalue), Compare-Cmdlets does not pick that up.

As-is, the script is made to run on demand from an interactive PowerShell session. Ideally, this would run scheduled and serverless from within the service, reporting changes by e-mail.

The script Compare-Cmdlets.ps1 can be downloaded from GitHub here. If you find this useful, would like to comment or have suggestions, use the comments below or leave them on GitHub.

Exchange Updates – September 2020

The Exchange Team released the quarterly Cumulative Updates for Exchange Server 2019 as well as Exchange 2016. Like recent Cumulative Updates for these products, they require .NET Framework 4.8. Apart from fixes as well as security updates included from the previous CU, the Exchange 2019 CU7 also comes with an update for the Exchange Sizing Calculator.

Links to the updates as well as a description of changes and fixes are described below.

VersionBuildKBDownloadUMLPSchemaPrepareAD
Exchange 2019 CU715.2.721.2KB4571787VLSC NY
Exchange 2016 CU1815.1.2106.2KB4571788DownloadUMLPNY

Exchange 2019 CU7 fixes:

  • 4570248 Get-CASMailbox uses wrong LDAP filter for ECPEnabled in Exchange Server 2019
  • 4576652 Updates for Exchange Server 2019 Sizing Calculator version 10.5
  • 4570252 Intermittent poison messages due to NotInBagPropertyErrorException in Exchange Server 2019
  • 4576649 System.InvalidCastException when you change passwords in Outlook on the web in Exchange Server 2019
  • 4570251 Inbox rule applying a personal tag doesn’t stamp RetentionDate in Exchange Server 2019
  • 4570245 ESEUtil /p fails if any long value (LV) is corrupted in Exchange Server 2019
  • 4570255 NullReferenceException occurs when running TestFederationTrust in Exchange Server 2019
  • 4576650 Can’t add remote mailbox when setting email forwarding in Exchange Server 2019 Hybrid environment
  • 4570253 CompletedWithErrors without details for mailbox migration batches in Exchange Server 2019
  • 4570247 CSV log of Discovery export fails to properly escape target path field in Exchange Server 2019
  • 4570246 EdgeTransport crashes with Event ID 1000 (exception code 0xc00000fd) in Exchange Server 2019
  • 4570254 MSExchangeMapiMailboxAppPool causes prolonged 100% CPU in Exchange Server 2019
  • 4563416 Can’t view Online user free/busy status in Exchange Server 2019
  • 4576651 Can’t join Teams meetings from Surface Hub devices after installing Exchange Server 2019 CU5
  • 4577352 Description of the security update for Microsoft Exchange Server 2019 and 2016: September 8, 2020

Exchange 2016 CU18 fixes:

  • 4570248 Get-CASMailbox uses wrong LDAP filter for ECPEnabled in Exchange Server 2016
  • 4570252 Intermittent poison messages due to NotInBagPropertyErrorException in Exchange Server 2016
  • 4576649 System.InvalidCastException when you change passwords in Outlook on the web in Exchange Server 2016
  • 4570251 Inbox rule applying a personal tag doesn’t stamp RetentionDate in Exchange Server 2016
  • 4570245 ESEUtil /p fails if any long value (LV) is corrupted in Exchange Server 2016
  • 4570255 NullReferenceException occurs when you run TestFederationTrust in Exchange Server 2016
  • 4576650 Can’t add remote mailbox when setting email forwarding in Exchange Server 2016 Hybrid environment
  • 4570253 CompletedWithErrors without details for mailbox migration batches in Exchange Server 2016
  • 4570247 CSV log of Discovery export fails to properly escape target path field in Exchange Server 2016
  • 4570246 EdgeTransport crashes with Event ID 1000 (exception code 0xc00000fd) in Exchange Server 2016
  • 4570254 MSExchangeMapiMailboxAppPool causes prolonged 100% CPU in Exchange Server 2016
  • 4563416 Can’t view Online user free/busy status in Exchange Server 2016
  • 4576651 Can’t join Teams meetings from Surface Hub devices after installing Exchange Server 2016 CU16
  • 4577352 Description of the security update for Microsoft Exchange Server 2019 and 2016: September 8, 2020

Notes:

  • These Cumulative Updates do not contain schema changes compared to their previous Cumulative Update.
  • There are Active Directory changes requiring you to run PrepareAD. Consult the Exchange schema versions page for object version numbers.
  • When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
  • Don’t forget to put the Exchange server in maintenance mode prior to updating. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
  • When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are allowed to trail at most one version (n-1).
  • If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
  • Cumulative Updates can be installed directly; no need to install RTM prior to installing Cumulative Updates.
  • Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
  • The order of installation shouldn’t matter with the “every server is an island” concept, yet recommended is to upgrade internet-facing, non-internet-facing servers first, followed by Edge Transports.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.

Security Updates Exchange 2016-2019 (Sep2020)

A quick blog on security updates for Exchange Server 2016 and Exchange Server 2019 released September 8th. These fixes address the following vulnerability:

  • CVE-2020-16875: Exchange Memory Corruption Vulnerability
    A remote code execution vulnerability exists in Microsoft Exchange server due to improper validation of cmdlet arguments. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the System user. Exploitation of the vulnerability requires an authenticated user in a certain Exchange role to be compromised. The security update addresses the vulnerability by correcting how Microsoft Exchange handles cmdlet arguments.

The exploits can be fixed by single security update, which you can find in the table below per current Exchange version.

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU6Download15.2.659.6KB4577352KB4540123
Exchange 2019 CU5Download15.2.595.6KB4577352KB4540123
Exchange 2016 CU17Download15.1.2044.6KB4577352KB4540123
Exchange 2016 CU16Download15.1.1979.6KB4577352KB4540123

Be advised that these security updates are Cumulative Update level specific. You cannot apply the update for Exchange 2016 CU17 to Exchange 2016 CU16. Also, the security update download has the same name for different Cumulative Updates, and I would suggest tagging the file name with the CU level, e.g. Exchange2016-CU17-KB4577352-x64-en.msp.

Also, run the Security Update from an elevated command prompt, to prevent issues during installation. And on a final note, as with any patch or update, I’d recommend to apply this in a acceptance environment first, prior to implementing it in production.

Exchange Online Management using EXOv2 module

Exchange2019Logo

Update (Aug6): Updated statement on viewing Application Sign-Ins in the Azure Active Directory > Sign-In view (currently in preview) – Thanks Ingo Gegenwarth .

Early June, Microsoft released a new PowerShell module
for managing Exchange Online. This module got announced at Ignite 2019 already, but it took
few months between going into preview end of last year before it finally reached Generally Available status. Usage of this module offers substantial improvements over the existing methods to connect to Exchange Online using Powershell, such as:

  • Leveraging the PowerShell module ecosystem to install and update the module. This as opposed to the click-to-run Microsoft Exchange Online Powershell Module or connecting through PowerShell remoting.
  • Support for Multi-Factor Authentication. This is something which the click-to-run module also offers but is not available when using PowerShell remoting.
  • Robustness. Existing sessions could easily timeout when you took a short break from the console. Or worse, your script could terminate in the middle of execution. This required you to reconnect or forced you to add resilience to your scripts by handling with these disconnects from the back end. The cmdlets of the EXOv2 module should be more robust and resilient.
  • Introduction of the Graph API support, which should show improvements in terms of speed. Microsoft indicated an 4-8 times improvement should be achievable, but your mileage may vary depending on the operation.
  • Support for PowerShell 6/7, core, and non-Windows operating systems is coming.

Exchange Online Management v2 module

The module has been baptized EXOv2 to indicate a major change compared to the click-to-run module (hereafter referred to as EXOv1), and also because it uses Graph API, just like the AzureAD v2 module. The module is available in the PowerShell Gallery, and installation is straightforward. Open a PowerShell 5.1 or later session in elevated mode and run:

Install-Module ExchangeOnlineManagement

The EXOv2 cmdlets which are REST-based and and leverage Graph API have their nouns prefixed with ‘EXO’, e.g. Get-EXOMailbox. Currently, there are 9 EXO cmdlets in the GA module, as well as few additional ones (more on those later). The regular commands such get Get-Mailbox are available as well after connecting to Exchange Online. This is similar behavior to the EXOV1 module, e.g.

Connect-ExchangeOnline [-UserPrincipalName <UPN>]

When required, satisfy the Multi-Factor Authentication logon process, and you
are done. Be advised that the EXOv2 module also supports
Delegated Access
Permissions
(DAP), allowing partners to connect to customer tenants by
specifying
-DelegatedOrganization <mycustomer.onmicrosoft.com>
when connecting.

Also note that apart from the EXO cmdlets, the current module also offers few other interesting commands and helper functions apart from the ones for housekeeping:

  • Connect-IPPSSession to connect to Security & Compliance center or Exchange Online Protection, depending on licensing. This command was also available in EXOv1.
  • Get-UserBriefingConfig & Set-UserBriefingConfig. These are a bit out of context, as these commands allow you to enable or disable the Cortana Briefing for users.
  • IsCloudShellEnvironment indicates if you are running from PowerShell or Azure Cloud Shell, which might be useful in scripts to determine the current context.

The EXOv2 cmdlets and their regular equivalents are shown in the table below:

EXO v1 or Remote
PowerShell
EXO v2
Get-MailboxGet-EXOMailbox
Get-MailboxFolderPermissionGet-EXOMailboxFolderPermission
Get-CASMailboxGet-EXOCASMailbox
Get-MailboxFolderStatisticsGet-EXOMailboxFolderStatistics
Get-MailboxPermissionGet-EXOMailboxPermission
Get-MobileDeviceStatisticsGet-EXOMobileDeviceStatistics
Get-RecipientGet-EXORecipient
Get-RecipientPermissionGet-EXORecipientPermission

What you might notice is the absence of any Set-EXO* cmdlets. This is true, and there is no word yet on if and when Set cmdlets will be introduced. That said, the biggest speed gain is often in bulk retrieval of data, not so much in altering one or more attributes. Until then, do not
de
spair though, as you can pipe output of the EXO cmdlets to their regular cmdlet,
e.g.

Get-EXOMailbox michel | Set-Mailbox -EmailAddresses @{Add='michel@myexchangelabs.com'}

This construction will also provide the additional benefit of parallel processing of objects as they pass through the pipeline, but more on that later.

Now comes another thing you should be aware of, and that is that these EXOv2 cmdlets might not use the same parameter sets as their v1 equivalent. Simply said, you cannot perform a simple Find and Replace operation in your script replacing Get-Mailbox with Get-EXOMailbox to start enjoying benefits of the new module.

When running a cmdlet like Get-EXOmailbox, you might notice that it returns only a subset of the attributes you might expect. Similar to what Properties does for Active Directory module, the EXOv2 module requires you to specify the individual Properties to return. Alternatively, you can use PropertySets to select a predefined set of attributes. For example, Get-EXOMailbox supports PropertySets such as All, Minimum (default), Policy, Quota and Retention to name a few. When needed, you can combine PropertySets, so something like the following is possible:

Get-EXOMailbox -Identity michel -PropertySets Quota,Policy

A small note on the PropertySet All: Just like Get-ADUser .. -Properties
*
is considered bad practice as you can impact resource usage and usually return more than what you need, using -PropertySets All
for every call is also a bad idea. All is convenient, but make sure you only return the data you need. Be a good person.

To see which EXOv2 cmdlets support PropertySets, use:

(Get-Command -Noun EXO* -Module ExchangeOnlineManagement).Where{$_.Parameters.propertySets}

Performance

Now, I suppose we want to get an indication of the performance enhancements by comparing EXOv2 and equivalent operation using v1 cmdlets. In this simple example we are returning quota information for some 50.000 mailboxes:

In this case, it is not the 4-8x improvement, but more than twice as fast is significant nonetheless. Especially if you are running interactively. To see the impact of parallel processing in the pipeline, we run the following:

As shown, there is a substantial increase in performance, but of course your mileage may vary depending on things like the number of objects, the attributes you require, and any filtering
applied.
Note that the PropertySet StatisticsSeed used in the example is a very minimal set of attributes which you can use if you only wish the refer to the objects, such as userPrincipalName, primarySmtpAddress and externalDirectoryObjectID.

Speaking of filtering, one would expect that server-side filtering (-Filter) would show an improvement in terms of speed over client-side filtering (Where), as filtering at the source is far more efficient in terms of result set and data to send over. However, it seems that due to the nature of a shared environment, sending superfluous data over the wire is less of a penalty than local filtering. Of course, your mileage may also vary here, so experiment what works best for your situation. Also, not every attribute is supported for filtering with these EXO cmdlets, which lies in how Graph exposes data. More information on that here.

When your session times out or disconnects, you will see that the module tries to reconnect your session; something which you would have to programmatically solve for the v1 module or regular remote PowerShell:

Certificate-based Authentication

Exchange administrators often have a requirement to run unattended scripts against Exchange Online, for example scheduled reports or as part of another process. In the past, this lead to setups where service accounts and stored credentials were used. Later this was improved by the ability to apply Conditional Access to limit these logons to on-premises infrastructure.

The problem with Multi-Factor Authentication is that it requires interaction with end-user to approve the sign-on. Of course, while your token is still valid, you can easily (re)connect to Exchange Online just by providing the Username Principal Name, which will reuse the token if it didn’t expire. But all in all, these solutions are high maintenance, and far from ideal from a security perspective.

Here comes certificate-based authentication. A preview version of the EXOv2 module was released end of June, which offers certificate-based authentication. In short, certificate-based authentication allows you to log on to Exchange Online using:

  • PowerShell
  • EXOv2 module
  • A (self-signed) certificate containing private key
  • Enterprise App registration in Azure Active Directory which contains the public key of this certificate, and proper assigned Azure AD role(s).

To install the EXOv2 preview module (v2.0.3 at time of writing), use:

Install-Module ExchangeOnlineManagement -AllowPrerelease

Note that it might complain if you have the GA version of the module installed, in which case you need to uninstall the GA module first, or you can install them side-by-side by specifying -Force.

Next, we need to create a self-signed certificate. To accomplish this, we can use the script published here. To create the certificate, simply use:

.\Create-SelfSignedCertificate.ps1 -CommonName 'EXOv2' -StartDate 7/30/2020 -EndDate 7/30/2021

Note that you need to provide a password to protect the PFX file containing the private key. Also do not forget to import the PFX in your local certificate store. When importing, you can mark the certificate as non-exportable, which prevents admins to transfer the certificate to other systems. After importing, you can check for the certificate’s presence using:

Get-ChildItem Cert:\CurrentUser\My | Where {$_.Subject -eq 'CN=EXOv2'}

The Subject should be the CommonName you used when generating the certificate. The thumbprint of our certificate is 49A4A73B4696718676770834BCD534DE35030D2C, which we will use later on to connect..

Now we need to set things up in Azure Active Directory:

  1. Open up the Azure Active Directory Portal, and navigate to Active Directory.
  2. Select App registrations, and click New registration.
  3. Give the App a meaningful Name, and select Accounts in this organizational directory only. Set Redirect URI to Web and leave the URL blank. Then, click Register.

    clip_image013[4]

    Note that our App has been assigned an Application (Client) ID. Make note of this value, as we will need it to connect later on.
  4. Next, we need to configure the App permissions. Select API permissions. User.Read should show up as default. Click Add a permission, and select Exchange (at the bottom). Select Application permissions, and in the next screen expand Exchange and check Exchange.ManageAsApp. We are done here, so click Add permissions.
  5. Only thing left now is to Grant admin consent, which can be done by clicking Grant admin consent for <tenant>. When done, the Status column for Exchange.ManageAsApp permission should have changed to Granted for <tenant>.

    clip_image015[4]
  6. Now we need to associate this App with out certificate. Select Certificates & Secrets, and click Upload certificate. Pick the certificate file which we generated earlier, and select Add.

    clip_image017[4]
  7. Last step is to assign the App one of the built-in Azure AD roles. Go to the Azure Active Directory blade, and select Roles and administrators. Unfortunately, only the following built-in Azure AD roles are supported at this moment:

    Global Reader, Global Administrator
    Security Reader, Security Administrator
    Helpdesk Administrator, Compliance Administrator
    Exchange Administrator

    Select one of the roles, and click Add assignments in the assignments overview screen. Note that when picking security principals, the App might not show up initially, and typing its first few letters might help. Click Add to assign the role.

    clip_image019[4]
    Note that the UserName mentioned in the overview is the Application ID.

Now we are done configuring the back end, we can look again at connecting. This should now be as simple as running:

Connect-ExchangeOnline -CertificateThumbprint '49A4A73B4696718676770834BCD534DE35030D2C' -AppId '0d3f8f4c-34fb-4a22-8466-80fd7379593b' -Organization '<tenant>.onmicrosoft.com'

Where:

  • CertificateThumbprint is the thumbprint of the self-signed certificate you created earlier.
  • AppID is the Application (Client) ID of the registered App.
  • <tenant>.onmicrosoft.com the initial domain name of your tenant.

Note that you can also connect specifying the CertificateFile instead of Thumbprint, but then you need to provide the password as well via CertificatePassword. Having the certificate in the certificate store of the administrator account or account running the task and just specifying the thumbprint is more convenient and requires zero interaction.

If all steps above were followed correctly, you should now be connected to Exchange Online, without any MFA interaction.

A final note is that Connect-IPPSSession mentioned earlier does not support certificate-base authentication.

What about other Workloads

You can use the same certificate-based authentication to connect to several other workloads as well. That is, provided you have installed the required PowerShell module and the Azure AD role you assigned to the Application has adequate permissions. You can use the commands below to connect to these workloads. A small note that the commands to connect may use a different parameter names for AppId or Organization, e.g. AppId, ApplicationId or ClientId and Organization and TenantId are same things in the examples below.

AzureAD (2.x or Preview)

Connect-AzureAD -CertificateThumbprint '49A4A73B4696718676770834BCD534DE35030D2C' -ApplicationId '0d3f8f4c-34fb-4a22-8466-80fd7379593b' -TenantId '<tenant>.onmicrosoft.com'

MicrosoftTeams (GA or Test)

Connect-Microsoftteams -CertificateThumbprint '49A4A73B4696718676770834BCD534DE35030D2C' -ApplicationId '0d3f8f4c-34fb-4a22-8466-80fd7379593b' -TenantId '<tenant>.onmicrosoft.com'

Microsoft Graph

Connect-Graph -CertificateThumbprint '49A4A73B4696718676770834BCD534DE35030D2C' -ClientId '0d3f8f4c-34fb-4a22-8466-80fd7379593b' -TenantId 'eightwone.onmicrosoft.com'


Audit

The logons which are performed in the context of the Application are viewable in the Azure Sign-Ins at https://aka.ms/iam/rtsp

Note that this view is currently in preview, and there might be a slight delay before logon shows up.

Final Notes

It would be nice if there would be a way to incorporate Exchange granular Role-Based Access Control model into the permissions model. Granting Apps only the built-in Azure AD roles is somewhat limiting, and it would be nice to restrict accounts in only being able to run the cmdlets and parameters they need to use.

When running Exchange cmdlets, you will find these in the audit log but with the <tenant>\AppID as UserName. Therefore, best thing to do is to use a single App registration for each individual administrator or process, instead of using a single App registration and multiple certificates.

And finally, it would be nice if the various teams would align their cmdlet and parameter naming schemes for consistency.

 

Configuring Exchange Online with IMAP & OAuth2

Not too long ago, the Exchange product group enabled Modern Authentication (or OAuth2) support for IMAP and SMTP in Exchange Online, and shortly after for POP3 as well. This support was much needed with the imminent deactivation of Basic Authentication. With Modern Authentication available, vendors, developers as well as organizations running custom scripts are given time to adopt Modern Authentication where applicable.

By delaying the original end date of Basic Authentication from October 13, 2020 to Q3’ish 2021 due to the Corona situation, the adoption period is increased significantly. That does not mean however developers and organizations can sit back and relax: Act sooner rather than later, the end of Basic Authentication is nigh.

The benefits of Modern Authentication are of course that it is a more secure model (e.g. resistant to password spray attacks), as well that it can leverage Microsoft 365 functionality like Conditional Access to limit protocols to certain locations.

That said, in this article I will show you how to approve usage of a popular 3rd party e-mail application Thunderbird, using IMAP protocol in conjunction with the Modern Authentication scheme. The procedures below have been run against Thunderbird 78.0b4 on Windows as well as Ubuntu.

Third Party Applications
Before we move on to Thunderbird, we first make sure the organization settings allow for third party applications to access your mailbox Exchange Online. This process has been blogged about for common popular applications, such as the native iOS Mail app or the Gmail app on Android. So, how to go ahead if your organization restricts access to third party applications, and they only want to allow specific applications, which is of course good practice.

The easiest way to add Thunderbird to the allowed applications and grant consent to the organization, is by constructing an admin consent URL. To construct the consent URL, take the following URL:

https://login.microsoftonline.com/<TenantID>/oauth2/authorize?client_id=<AppID>&response_type=code&prompt=admin_consent

and,

  1. Replace <TenantID> with your Tenant ID. This piece of information can be found under the Azure Active Directory blade in the Azure portal.
  2. Replace <AppID> with the Application ID (sometimes also referred to as Client ID) of the application you want to provide consent for. As we can see in the table below, the ID of Thunderbird is 08162f7c-0fd2-4200-a84a-f25a4db0b584.
ApplicationID
Thunderbird08162f7c-0fd2-4200-a84a-f25a4db0b584
Gmail app2cee05de-2b8f-45a2-8289-2a06ca32c4c8
iOS Accounts (Apple Mail app)f8d98a96-0999-43f5-8af3-69971c7bb423

Open your browser, and visit this URL as an administrator. You will be greeted with a consent form, in which you will be asked to accept for your organization. Because the redirect_uri is empty here, you will likely be send to a non-existing location after giving consent, but that’s OK.

When you look at the Enterprise Applications blade in the Azure Portal, you will notice the Thunderbird app has been added. Here you can further customize it, like any enterprise application supporting Modern Authentication, e.g.

  • Restrict access to specific users or groups.
  • Use Conditional Access to restrict access to certain locations.
clip_image001

Another thing to note is that permissions for Thunderbird app will have been translated to the following Graph permissions:

APIPermissionType
Microsoft GraphRead and write access to mailboxes via IMAP.Delegated
Microsoft GraphRead and write access to mailboxes via POP.Delegated
Microsoft GraphRead and write access to mailboxes via SMTP AUTH.Delegated
Microsoft GraphSign in and read user profile.Delegated

We should now be ready on the back-end.

Thunderbird
Now as an end user, start Thunderbird. Do not start configuring the account yet, as we first need to modify a Thunderbird setting to allow for successful Modern Authentication through a browser popup. Click the ‘hamburger’ menu to open the Options window. Scroll all the way down, and open the Config Editor. Click ‘I Accept the risk’. In the settings overview, set General.UserAgent.CompatMode.Firefox setting to True:

Preference NameStatusTypeValue
general.useragent.compatMode.firefoxmodifiedbooleanTrue

Close the Config Editor and Preferences tab. We can now set up our account in Thunderbird.

Select Add Mail Account, and enter your name and e-mail address. You can leave the password empty, as we will be using an Oauth token which we will retrieve later on. Press Continue to have Thunderbird figure out where your mailbox is hosted. When it properly discovers the mailbox location, it will set the configuration as follows:

image

If Thunderbird can’t figure out your settings (for some reason the Windows build could, but the Ubuntu build couldn’t), configure them as indicated above. We can’t select OAuth2 for authentication here, so leave Authentication as is; we will correct this right after we click Done.

Note: Configure manually would be the place you expect to set authentication to OAuth2 straight away, but with the build we used, the OAuth2 option is not available from the manual account setup dialog. Therefore, we need to set up the account and correct settings afterwards.

  1. In the Server Settings window related to your account, select OAuth2 authentication:
    clip_image001[14]
  2. In the Outgoing Server (SMTP) settings, select Offic365 (Microsoft) – smtp.office365.com, click Edit and set authentication for outbound SMTP to OAuth2 as well.
    clip_image002
    Note: The Thunderbird build running on Ubuntu doesn’t provide the OAuth2 authentication option for SMTP.

When finished, click ‘Get Messages’. The familiar Microsoft 365 authentication browser dialog should show up. After signing in, the next question will be to grant consent to the Thunderbird application to it can access your mailbox data and send e-mail:

clip_image001[18]

Note that this dialog can not be suppressed, as currently only interactive applications are supported. If you are working on an app or script which needs unattended access, please use Graph API.

After the user provides consent, Thunderbird is ready and will start fetching your default folders and mail items. If you want to view additional folders, you need to subscribe to them by right-clicking the account and picking Subscribe. Only folders with mail-items are supported, despite you can select every folder in your mailbox including Calendar or Contacts.

Logging
If you have people in your organization requiring some form of proof that Modern Authentication is being used, you can use the Enterprise Applications / Sign-Ins view from the Azure Active Directory portal.

Alternatively, you can use Thunderbird’s built-in logging capabilities. To accomplish the latter, set the following environment variables before starting Thunderbird:

MOZ_LOG=IMAP:5,timestamp
MOZ_LOG_FILE=%APPDATA%\ThunderBird-imap.log

In the generated ThunderBird-imap.log file like shown below, you should be able to spot Modern Authentication (XOAuth2) being selected:

2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: I/IMAP 259C3800:outlook.office365.com:NA:CreateNewLineFromSocket: * CAPABILITY IMAP4 IMAP4rev1 AUTH=PLAIN AUTH=XOAUTH2 SASL-IR UIDPLUS MOVE ID UNSELECT CHILDREN IDLE NAMESPACE LITERAL+2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: D/IMAP ReadNextLine [stream=1991DE80 nb=28 needmore=0]
2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: I/IMAP 259C3800:outlook.office365.com:NA:CreateNewLineFromSocket: 1 OK CAPABILITY completed.
2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: D/IMAP Try to log in
2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: D/IMAP IMAP auth: server caps 0x840087635, pref 0x800000000, failed 0x0, avail caps 0x800000000
2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: D/IMAP (GSSAPI = 0x1000000, CRAM = 0x20000, NTLM = 0x100000, MSN = 0x200000, PLAIN = 0x1000, LOGIN = 0x2, old-style IMAP login = 0x4, auth external IMAP login = 0x20000000, OAUTH2 = 0x800000000)
2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: D/IMAP Trying auth method 0x800000000
2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: D/IMAP IMAP: trying auth method 0x800000000
2020-06-30 13:10:16.726000 UTC - [(null) 15696: IMAP]: D/IMAP XOAUTH2 auth
2020-06-30 13:10:16.775000 UTC - [(null) 15696: IMAP]: D/IMAP ReadNextLine [stream=280D87C0 nb=180 needmore=0] 2020-06-30 13:10:16.775000 UTC - [(null) 15696: IMAP]: I/IMAP 2089A000:outlook.office365.com:NA:CreateNewLineFromSocket: * OK The Microsoft Exchange IMAP4 service is ready. [QQBNADQAUABSADAAMQAwADEAQwBBADAAMAA3ADYALgBlAHUAcgBwAHIAZAAwADEALgBwAHIAbwBkAC4AZQB4AGMAaABhAG4AZwBlAGwAYQBiAHMALgBjAG8AbQA=]

Exchange Updates – June 2020

The Exchange Team released the quarterly Cumulative Updates for Exchange Server 2019 as well as Exchange 2016. Like the previous two Cumulative Updates, these require .NET Framework 4.8.

Apart from fixes as well as security updates included from the previous CU, these update contain the following changes for both builds:

  • Added additional file types to default OWA Mailbox Policy for Blocked File Extensions. More information in KB4559446.
  • Added support to Restore-RecoverableItems for easier usage. More details in KB4547707.

Links to the updates as well as a description of changes and fixes are described below.

VersionBuildKBDownloadUMLPSchema
Exchange 2019 CU615.2.659.4KB4556415VLSC N
Exchange 2016 CU1715.1.2044.4KB4556414DownloadUMLPN

Exchange 2019 CU6 fixes:

  • 4559441 Foreign language characters set in RejectMessageReasonText of a transport rule aren’t shown correctly in Exchange Server 2019
  • 4547707 Enable piping for Restore-RecoverableItems in Exchange Server 2019
  • 4549689 HMA EvoSTS certificate rollover causes authentication prompts due to stalled key on worker process spawn (warmup phase) in Exchange Server 2019
  • 4559446 Changes to Outlook on the web blocked file extensions and MIME types in Exchange Server 2019
  • 4559440 Export to a PST for an eDiscovery search fails Exchange Server 2019
  • 4559439 EAS creates failure report if a message with unknown recipients is in Drafts in Exchange Server 2019
  • 4559442 2080 Events caused by empty values in HKLM\SYSTEM\CurrentControlSet\Services\MSExchange ADAccess\Instance0 in Exchange Server 2019
  • 4559438 Edge Transport server hangs in Exchange Server 2019
  • 4559443 Managed Folder Assistant fails with Event ID 9004 NotInBagPropertyErrorException in Exchange Server 2019
  • 4559437 PR_RECIPIENT_ENTRYID is computed if no email address or type in Exchange Server 2019
  • 4559444 Conversion from HTML to RTF removes non-breaking space in Exchange Server 2019
  • 4559436 Attachments with properties (like Azure Information Protection labels) not always matching in Exchange Server 2019
  • 4559435 Introduce an OrganizationConfig flag to enable or disable recipient read session in Exchange Server 2019

Exchange 2016 CU17 fixes:

  • 4559444 Conversion from HTML to RTF removes non-breaking space in Exchange Server 2016
  • 4559435 Introduce an OrganizationConfig flag to enable or disable recipient read session in Exchange Server 2016
  • 4547707 Enable piping for Restore-RecoverableItems in Exchange Server 2019 and 2016
  • 4559436 Attachments with properties (like Azure Information Protection labels) don’t always match in Exchange Server 2016
  • 4559437 PR_RECIPIENT_ENTRYID is computed if no email address or type in Exchange Server 2016
  • 4559438 Edge Transport server hangs in Exchange Server 2016
  • 4559439 EAS creates failure report if a message with unknown recipients is in Drafts in Exchange Server 2016
  • 4559440 Export to a PST for an eDiscovery search fails in Exchange Server 2016
  • 4559441 Foreign language characters set in RejectMessageReasonText of a transport rule aren’t shown correctly in Exchange Server 2016
  • 4559442 2080 Events caused by empty values in HKLM\SYSTEM\CurrentControlSet\Services\MSExchange ADAccess\Instance0 in Exchange Server 2016
  • 4549689 HMA EvoSTS certificate rollover causes authentication prompts due to stalled key on worker process spawn (warmup phase) in Exchange Server 2016
  • 4559443 Managed Folder Assistant fails with Event ID 9004 NotInBagPropertyErrorException in Exchange Server 2016
  • 4559446 Changes to Outlook on the web blocked file extensions and MIME types in Exchange Server 2016

Notes:

  • These Cumulative Updates do not contain schema changes compared to their previous Cumulative Update.
  • When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
  • Don’t forget to put the Exchange server in maintenance mode prior to updating. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
  • When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to delay installing at most one version (n-1).
  • If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
  • Cumulative Updates can be installed directly; no need to install RTM prior to installing Cumulative Updates.
  • Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
  • The order of installation shouldn’t matter with the “every server is an island” concept, yet recommended is to upgrade internet-facing, non-internet-facing servers first, followed by Edge Transports.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.

MS Teams & pre-Exchange 2016CU3

Updated May 9th: Added Share to Teams. to table

With the emergency to facilitate working from home due to the Corona pandemic, many organizations were faced with a dilemma. When running Exchange 2013 or some even Exchange 2010 on-premises, and a desire to start using Microsoft Teams, organizations were confronted with the following requirements for integrating Microsoft Teams with Exchange on-premises (source):

  • Users with mailboxes hosted on-premises must be synchronized to Azure Active Directory.
  • Running Exchange 2016 Cumulative Update 3 or later on-premises.
  • OAuth needs to be configured (via Hybrid Configuration Wizard, or manual as MVP fellow Jaap blogged about here).
  • Recently, an additional requirement was added to explain that for delegates to schedule calendar meetings on behalf of another person, some additional steps are required (steps 2-3 mentioned here).

Now as you might know, Exchange 2010 does not support OAuth authentication. But, by putting Exchange 2016 in front of Exchange 2010, Exchange 2016 can be used for dealing with OAuth authentication, as well as dealing with client traffic as it can down-level proxy to Exchange 2010 for mailboxes hosted on those servers. Looking at these requirements, organizations might conclude that putting Exchange 2016 CU3 in front of their Exchange environment, and configuring OAuth would suffice the requirement to integrate Teams with their Exchange on-premises environment.

image

Alas, the additional requirement for full Teams integration is that the mailbox server hosting the mailbox should support REST API. Teams leverages Graph REST API calls to interact with mailboxes. In an Hybrid Exchange setup, on-premises mailboxes are identified, and related REST API calls will be directed at the on-premises REST endpoint, landing on your Exchange environment. The requirement for REST API support is something which is not explicitly stated in the Teams integration article, despite my earlier pull request.

It is however stated implicitly in an article on REST support in Hybrid Exchange or the original publication on REST API support in Exchange 2016 CU3 by the Exchange PG, two articles which you might easily have missed or forgotten about. Either way, it states that “All on-premises mailboxes that will use the REST APIs must be located on databases located on Exchange 2016 CU3 servers”.

Thus, with REST API support only being available per Exchange 2016 CU3, Teams will not fully integrate with mailboxes hosted on earlier versions of Exchange. Exchange 2016 can be used to offload OAuth when your mailbox is still on Exchange 2010 (which works fine for Exchange Web Services for Free/Busy, for example), but Exchange 2010 does not support REST API, and thus will never understand those ‘weird’ (proxied) requests landing on /api virtual directory, typical of REST API calls. Consequently, you will see AutodiscoverV2 and REST API calls greeted with a 404:

2020-04-29 20:22:52 fd86:b628:2775:1:9502:cdcc:d4b1:5950 GET /autodiscover/autodiscover.json Email=chefke%40contoso.com&Protocol=REST&RedirectCount=1 443 CONTOSO\EX2$ fd86:b628:2775:1:9f8:2d9:c8a1:3c4a SkypeSpaces/1.0a$*+ 404 0 2 31

Typically, first thing users usually will notice missing is the Calendar integration:

image

Knowing this, the assumption could be that this combination doesn’t work at all, but as often the truth lies somewhere in the middle. You can use Teams when mailboxes are still hosted on pre-Exchange 2016 CU3, if you can live with the limitations. Below I have included a short overview of these, or other noteworthy items. The information is complementary to the How Exchange and Teams interact article. I hope it may help in discussions on what works and what doesn’t.

Disclaimer: Validated with mailbox hosted on Exchange 2010 with Exchange 2016 in front, OAuth and SkypeOnline AppId configured, and using Outlook 2016 C2R. Information may be subject to change. The list may not be conclusive; if you have any additional observations, please leave them in the comments.

ActionsWorksComment
Create & View Meetings in TeamsNoNo Calendar integration as this requires Outlook Calendar REST API. Visual clue is absence of the Calendar button.
Modify User Photo in Teams (client)NoDoesn’t work when mailbox is hosted in Exchange on-premises.
Call HistoryYesHistory doesn’t propagate to mailboxes hosted in Exchange on-premises in ‘Teams Calls’ folder. Does
Access Outlook ContactsNoWorks only with Exchange Online mailboxes.
VoicemailYesMay use & receive voice-mail, but can’t play from Teams.
Free/Busy statusYesUses EWS.
Create & View/Update Teams Meetings from OutlookYesUsing default Teams Meeting add-in.
Create Teams Meetings from Outlook as DelegateNoTeams Scheduler uses AutodiscoverV2 to discover delegate EWS endpoint, and fails. Outlook will display “Sorry, but we can’t connect to the server right now. Please try again later.”
View/Update Teams Meetings from Outlook as DelegateYesEWS is used to fetch and update the calendar item.
MailTips in TeamsNoMailTips like Out of Office are not shown in Teams. MailTips work for Exchange 2016 CU3+.
Create & View Channel Meetings in TeamsNoDoesn’t work when mailbox is hosted in Exchange on-premises.
Share to TeamsNoDoesn’t work when mailbox is hosted in Exchange on-premises.

Of course, the better experience is to be had when your mailbox is hosted on Exchange 2016 CU3 or later (including Exchange 2019), or best when you simply host them in Exchange Online. However, given the circumstances and pressure from the organization to use Teams, that route might not be an option for everyone. Organizations may look at substantial investments in time and resources. In those cases, it might be good to know of alternative less preferable scenarios, and more important, any possible limitations you might encounter when taking a shortcut.

Exchange Updates – March 2020

The Exchange Team released the quarterly Cumulative Updates for Exchange Server 2019 as well as Exchange 2016. Like the previous Cumulative Updates, these require .NET Framework 4.8. Apart from fixes as well as security updates included from the previous CU, these update contain the following changes for Exchange 2019 CU5:

  • Updated Exchange calculator (v10.4).
  • Fixes an issue with Manage-MetaCacheDatabase.ps1 to configure MCDB.
  • Fixes partial word searches when using Outlook in online mode.

Links to the updates as well as a description of changes and fixes are described below.

VersionBuildKBDownloadUMLPSchema
Exchange 2019 CU515.2.595.3KB4537677VLSC N
Exchange 2016 CU1615.1.1979.3KB4537678DownloadUMLPN

Exchange 2019 CU5 fixes:

  • 4552472 Exchange Server 2019 Sizing Calculator version 10.4 is available
  • 4536552 Export-ModernPublicFolderStatistics.ps1 is not working in Exchange Server 2019
  • 4538303 Exchange 2019 Setup Prerequisite Check fails for .NET 4.8 Framework in CU4 on Windows builds 1909 and 1903
  • 4547705 Authentication loop between msft.sts.microsoft.com/adfs and OWA in Exchange Server 2019
  • 4547706 Birthday isn’t correctly synced to iOS native mail app in Exchange Server 2019
  • 4547708 Elevation of privileges possible when Active Directory permissions role is granted in Exchange Server 2019
  • 4547709 InternetWebProxyBypassList is ignored by Mailbox Replication service in Exchange Server 2019
  • 4547710 New-MailboxSearch with In-Place Hold enabled replaces all values in msExchUserHoldPolicies if adding a value in Exchange Server 2019
  • 4547711 Public folder permissions aren’t applied from Outlook in Exchange Server 2019 hybrid environment
  • 4547712 Outlook on the web (OWA) exposes junk operations even if disabled via OwaMailboxPolicy in Exchange Server 2019
  • 4547713 IsOnlineMeeting is always false for Teams-only meetings in Exchange Server 2019
  • 4547714 Can’t add remote shared mailbox using ECP into distribution group in Exchange Server 2019 hybrid environment
  • 4547715 New created search folder retention policy is changed in Exchange Server 2019
  • 4547719 MCDB status is “Offline” and SSDs are not formatted in Exchange Server 2019
  • 4547720 Partial word searches not working for mailboxes in Outlook online mode in Exchange Server 2019
  • 4547721 Exchange Sizing Calculator still supports mail.que database over 2 TB in Exchange Server 2019
  • 4547722 Can’t go from Office 365 to Enterprise in Exchange Server 2019 Exchange admin center (EAC) if Chrome SameSite Cookie is enabled
  • 4547723 Can’t sign in to Office 365 if configuring hybrid with Chrome SameSite Cookie enabled in Exchange Server 2019
  • 4536987 Description of the security update for Microsoft Exchange Server 2019: February 11, 2020

Exchange 2016 CU16 fixes:

  • 4547705 Authentication loop between msft.sts.microsoft.com/adfs and OWA in Exchange Server 2016
  • 4547706 Birthday isn’t correctly synced to iOS native mail app in Exchange Server 2016
  • 4547708 Elevation of privileges possible when Active Directory permissions role is granted in Exchange Server 2016
  • 4547709 InternetWebProxyBypassList is ignored by Mailbox Replication service in Exchange Server 2016
  • 4547710 New-MailboxSearch with In-Place Hold enabled replaces all values in msExchUserHoldPolicies if adding a value in Exchange Server 2016
  • 4547711 Public folder permissions aren’t applied from Outlook in Exchange Server 2016 hybrid environment
  • 4547712 Outlook on the web (OWA) exposes junk operations even if disabled via OwaMailboxPolicy in Exchange Server 2016
  • 4547713 IsOnlineMeeting is always false for Teams-only meetings in Exchange Server 2016
  • 4547714 Can’t add remote shared mailbox by using ECP into distribution group in Exchange Server 2016 hybrid environment
  • 4547715 New created search folder retention policy is changed in Exchange Server 2016
  • 4547722 Can’t go from Office 365 to Enterprise in Exchange Server 2016 Exchange admin center (EAC) if Chrome SameSite Cookie is enabled
  • 4547723 Can’t sign in to Office 365 if configuring hybrid with Chrome SameSite Cookie enabled in Exchange Server 2016
  • 4547716 Event ID 1325 and Test-ExchangeSearch crashes application pool with NullReferenceException in Exchange Server 2016
  • 4536987 Description of the security update for Microsoft Exchange Server 2016: February 11, 2020

Notes:

  • These Cumulative Updates do not contain schema changes compared to their previous Cumulative Update.
  • When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
  • Don’t forget to put the Exchange server in maintenance mode prior to updating. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
  • When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to delay installing at most one version (n-1).
  • If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
  • Cumulative Updates can be installed directly; no need to install RTM prior to installing Cumulative Updates.
  • Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
  • The order of installation shouldn’t matter with the “every server is an island” concept, yet recommended is to upgrade internet-facing, non-internet-facing servers first, followed by Edge Transports.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.

Security Updates Exchange 2010-2019 (Feb2020)

A quick blog on recently published security updates for Exchange Server 2013 up to Exchange Server 2019 and Exchange Server 2010 as well. These fixes address the following vulnerabilities:

  • CVE-2020-0692: Microsoft Exchange Server Elevation of Privilege Vulnerability

An elevation of privilege vulnerability exists in Microsoft Exchange Server. An attacker who successfully exploited this vulnerability could gain the same rights as any other user of the Exchange server. This could allow the attacker to perform activities such as accessing the mailboxes of other users. Exploitation of this vulnerability requires Exchange Web Services (EWS) to be enabled and in use in an affected environment. To exploit the vulnerability, an attacker would need to change parameters in the Security Access Token and forward it to a Microsoft Exchange Server, thereby allowing impersonation of another Exchange user. To address this vulnerability, Microsoft has changed the way EWS handles these tokens.
This vulnerability does not apply to Exchange 2010.

  • CVE-2020-0688: Microsoft Exchange Memory Corruption Vulnerability

A remote code execution vulnerability exists in Microsoft Exchange Server when the server fails to properly create unique keys at install time. Knowledge of a the validation key allows an authenticated user with a mailbox to pass arbitrary objects to be deserialized by the web application, which runs as SYSTEM. The security update addresses the vulnerability by correcting how Microsoft Exchange creates the keys during install.

The CVE documents contain more details on the vulnerabilities. In addition, KB4536989 (Rollup 30) for Exchange 2010 and KB4536988 for Exchange 2013 also fixes the following issue:

  • KB4540267 MSExchangeDelivery.exe or EdgeTransport.exe crashes in Exchange Server 2013 and Exchange Server 2010

The exploits can be fixed by single security update, which you can find in the table below per current Exchange version.

ExchangeDownloadBuildKBSupersedes
Exchange 2019 CU4Download15.2.529.8KB4536987KB4523171
Exchange 2019 CU3Download15.2.464.11KB4536987KB4523171
Exchange 2016 CU15Download15.1.1913.7KB4536987KB4523171
Exchange 2016 CU14Download15.1.1847.7KB4536987KB4523171
Exchange 2013 CU23Download15.0.1497.6KB4536988KB4523171
Exchange 2010 SP3 RU30KB4536989KB4509410

Be advised that the Security Updates for Exchange 2013-2019 are Cumulative Update level specific. Unfortunately, the security update carries the same name for different CUs, and you cannot apply the update for Exchange 2016 CU15 to Exchange 2016 CU14. I would suggest tagging the Cumulative Update in the file name used, e.g. Exchange2016-CU15-KB4536987-x64-en.msp.

Also, run the Security Update from an elevated command prompt, to prevent issues during installation. And on a final note, as with any patch or update, I’d recommend to apply this in a acceptance environment first, prior to implementing it in production.

Exchange Updates – December 2019

Exchange2019Logo

The Exchange Team released the quarterly Cumulative Updates for Exchange Server 2019 as well as Exchange 2016. One significant change with these updates is the requirement for .NET Framework 4.8, as announced earlier. Also, Exchange 2019 CU4 comes with an updated Exchange calculator. Links to the updates as well as a description of changes and fixes are described below.

VersionBuildKBDownloadUMLPSchema
Exchange 2019 CU415.2.529.5 KB4522149VLSC N
Exchange 2016 CU1515.1.1913.5 KB4522150DownloadUMLPN

Exchange 2019 CU4 fixes:

  • 4528696 Exchange PowerShell cmdlets take longer time to run in Exchange Server 2019
  • 4528695 Event ID 4009 when using SubjectOrBodyMatchesPatterns on Edge server in Exchange Server 2019
  • 4528694 Can’t open .ics file in Outlook on the web in Exchange Server 2019
  • 4528692 “A parameter was specified that isn’t valid” error when creating transport rule in Exchange Server 2019
  • 4523519 Set-SendConnector doesn’t work for Exchange Server in hybrid scenarios with Edge Server installed
  • 4528688 Only one recipient shows when saving draft by using Exchange ActiveSync version 16.0 in Exchange Server 2019
  • 4528693 Get-CalendarDiagnosticLog is proxied for queries within the same forest in Exchange Server 2019
  • 4528687 NotificationClient logs aren’t purged and consume lots of disk in Exchange Server 2019
  • 4528689 Outlook on the web shows MailTip when recipients equal the large audience size in Exchange Server 2019
  • 4528690 Can’t move or delete folder in Outlook online mode if the destination has a folder with the same name in Exchange Server 2019
  • 4532744 System.ArgumentNullException when you use Set-user to assign block legacy auth policy in Exchange Server 2019
  • 4532747 Address list separation not working for a user without a mailbox in Exchange Server 2019
  • 4523171 Description of the security update for Microsoft Exchange Server 2019, 2016, and 2013: November 12, 2019

Exchange 2016 CU15 fixes:

  • 4515256 “The function cannot be performed…” error when you send a message that’s open for a long time in Exchange Server 2016
  • 4528693 Get-CalendarDiagnosticLog is proxied for queries within the same forest in Exchange Server 2016
  • 4523519 Set-SendConnector doesn’t work for Exchange Server in hybrid scenarios with Edge Server installed
  • 4528690 Can’t move or delete folder in Outlook online mode if the destination has a folder with the same name in Exchange Server 2016
  • 4528687 NotificationClient logs aren’t purged and consume lots of disk in Exchange Server 2016
  • 4528689 Outlook on the web shows MailTip when recipients equal the large audience size in Exchange Server 2016
  • 4528688 Only one recipient shows when saving draft by using Exchange ActiveSync version 16.0 in Exchange Server 2016
  • 4528695 Event ID 4009 when using SubjectOrBodyMatchesPatterns on Edge server in Exchange Server 2016
  • 4528694 Can’t open .ics file in Outlook on the web in Exchange Server 2016
  • 4528692 “A parameter was specified that isn’t valid” error when creating transport rule in Exchange Server 2016
  • 4515257 Hash mismatch is reported for Exchange DLLs in the bin directory of Exchange Server 2016
  • 4528696 Exchange PowerShell cmdlets take longer time to run in Exchange Server 2016
  • 4532747 Address list separation not working for a user without a mailbox in Exchange Server 2016
  • 4523171 Description of the security update for Microsoft Exchange Server 2019, 2016, and 2013: November 12, 2019

Notes:

  • These Cumulative Updates do not contain schema changes compared to their previous Cumulative Update.
  • When upgrading from an n-2 or earlier version of Exchange, or an early version of the .NET Framework, consult Upgrade Paths for CU’s & .NET.
  • Don’t forget to put the Exchange server in maintenance mode prior to updating. Regardless, setup will put the server in server-wide offline mode post-analysis, before making actual changes.
  • When using Exchange hybrid deployments or Exchange Online Archiving (EOA), you are required to delay installing at most one version (n-1).
  • If you want to speed up the update process for systems without internet access, you can follow the procedure described here to disable publisher’s certificate revocation checking.
  • Cumulative Updates can be installed directly; no need to install RTM prior to installing Cumulative Updates.
  • Once installed, you can’t uninstall a Cumulative Update nor any of the installed Exchange server roles.
  • The order of installation shouldn’t matter with the “every server is an island” concept, yet recommended is to upgrade internet-facing, non-internet-facing servers first, followed by Edge Transports.

Caution:

As for any update, I recommend to thoroughly test updates in a test environment prior to implementing them in production. When you lack such facilities, hold out a few days and monitor the comments on the original publication or forums for any issues.