Old Message Tracing Components Will be Deprecated in September 2025

The June 3 announcement that the new Exchange Online Message Trace facility is generally available creates some work for Microsoft 365 tenant administrators who use message trace in scripts. The roll-out of the update will happen between mid-June and July 2025. Tenants that participated in the public preview and have V3.7 or later of the Exchange Online management module can already use the new Get-MessageTraceV2 and Get-MessageTraceDetailV2 cmdlets.

In the announcement, Microsoft says that they will deprecate the old message tracing UI from the Exchange admin center and the old Get-MessageTrace and Get-MessageTraceDetail cmdlets beginning September 1, 2025. Microsoft will also deprecate the background reporting web service that responds to requests for online message trace data at the same time. The deployment is limited to commercial tenants and doesn’t currently affect sovereign clouds because of the need to certify code upgrades for those environments.

Time Slipping Away to Upgrade Code

Microsoft will take care of updating the Exchange admin center. Customers and ISVs that depend on the old implementation of message tracing must complete their upgrade by the end of August 2025 before the deprecation cycle begins. If you don’t, the risk is that code will stop working without notice.

Twelve weeks seems like a reasonable amount of time to find and update code. However, we’re heading into a peak vacation period when availability of developers becomes more problematic, so now’s the time to get going.

Checking What’s Needed to Upgrade Scripts

To check out what’s needed, I upgrade two scripts. The first script reports email sent to external recipients by members of a distribution list. The second reports the numbers of outbound and inbound messages sent from domains (Figure 1). The updated scripts are both available in the Office 365 IT Pros GitHub repository (see links in the articles).

Updating the first script was easy. All I needed to do was swap out calls to the Get-MessageTrace cmdlet and replace them with Get-MessageTrace2.

The second script was harder because it used paging to fetch pages containing 1,000 message tracing records. Microsoft’s public preview announcement said that they removed support for pagination. The new mechanism behaves awfully like pagination in that you need to fetch message tracing events in batches of up to 5,000 records until all available data is retrieved. Unlike the pagination used by Graph-based APIs, next link URLs are not used to indicate the point the next set of events start. Instead, fetching based on a mixture of dates and email addresses.

An example is worth many words, so if you’re confused about how to fetch message tracing data, have a look at the script for the second example.

Extended Range of Historical Data Available

According to the public preview announcement, Microsoft plans to deliver the ability to query up to 90 days of historical message tracing data. Initially, Microsoft plans to have 30 days of historical message tracing data available online. However, a single query is limited to ten days, so fetching the message tracing data for 30 days requires three separate queries, each covering a 10-day period. If you fetch data for more than 10 days, Exchange responds with the error message:

Error fetching message trace data: ||The interval between StartDate and EndDate can’t be longer than 10 days.

Not a Difficult Transition

Moving to the new message tracing facility isn’t hard. It shouldn’t take too long to upgrade scripts as the changes are straightforward (and having an example helps). Time is likely to be the problem. Too many competing demands for PowerShell coding, too little time to get everything done.

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