Weekly Update 21 July 2025 – BYOA in Microsoft 365 Copilot, Copilot in EWS Migration, Copilot Search

This week:

Bring your own agents into Microsoft 365 Copilot

Supercharge your EWS migration with AI and GitHub Copilot

Searching for Answers About M365 Copilot Search 

You can also listen to the audio-only version: Thoughtstuff Podcast – Tom Morgan on Teams Dev: Weekly Update 21 July 2025.

Find all my videos at thoughtstuff.co.uk/videos. You can also subscribe to the audio-only version of these videos, either via iTunes, Spotify or your own podcasting tool.

Transcript (AI-Generated)

Weekly Update – Microsoft 365 Developer News

Hello. Welcome to another weekly update. I hope you’re doing well. I’m back after a week off. Before that, we didn’t really have anything to talk about apart from some tech news – Microsoft layoffs and the new fiscal year and all that. But we’re back, and although the news is still light, there are a few things worth discussing.

Bring Your Own Agents in Microsoft 365 Copilot

The first item is a blog post titled Bring Your Own Agents into Microsoft 365 Copilot. If you thought this was already a thing, well, it’s now officially available, but with a nuance: the blog post refers specifically to custom engine agents.

This highlights a broader challenge in the developer landscape – multiple similar-sounding tools and features make it easy to confuse them. This is one of the few ways to build custom Microsoft 365 Copilot agents using the Microsoft 365 Agents SDK – not to be confused with the Agents Toolkit.

These are the most flexible agents currently available. You can build your solution using Azure AI Foundry, bring your own models, and write all the code yourself if you want. It’s high effort, but high control. They are now generally available and show up in the Agents list in Microsoft 365 Copilot. Development is possible via what used to be the Teams Toolkit, now called the Microsoft 365 Agents Toolkit.

Migrating from Exchange Web Services (EWS)

Next up – a reminder that support for EWS ends in October 2026. There is now a tutorial available to help you migrate away from EWS, which uses AI and IntelliSense to scan your codebase for deprecated APIs. This is especially helpful if you’ve inherited a legacy codebase.

The tutorial also makes heavy use of Copilot to help walk you through migrating to Microsoft Graph. It’s a helpful tool, but comes with a caveat – you should always understand what the generated code is doing. Blind trust in AI risks painting yourself into a corner you can’t get out of.

Copilot Search Arrives

Finally, the long-anticipated semantic search in Microsoft 365 Copilot is rolling out. David Berry at Directions on Microsoft wrote a helpful post summarizing what users and developers can expect. A semantic search feature is core to delivering relevant information inside Copilot experiences. It’s great to see progress here.

I’ll be keeping a close eye on what API support emerges alongside this feature because enabling third-party access is just as important for real-world use cases. Better search doesn’t just need to appear in the UI – it needs to power our custom apps, bots, and workflows.

Looking Ahead

That’s it for now. Although summer tends to be a quiet time for updates, I expect September to bring clearer direction and more announcements, especially as Microsoft completes internal reorgs and begins its fiscal year planning.

Have a great week, and I’ll see you next time!