The September 2026 Power BI Updates in Plain Language
Microsoft ships a Power BI update every month. Most months I pull out the handful of things that change how the work actually feels, try them on real data, and write up what helped. This is September, written up a few weeks after the fact because the release is large enough to be worth doing properly.
It is the biggest release of the year so far, timed to the European Microsoft Fabric and SQL Community Conference in Barcelona. The Copilot and AI section alone runs to eight items. I have been posting some of the highlights on LinkedIn one feature at a time, and this is all of it in one place, including the parts that did not make it into those posts.
If you only read one line: Power BI Projects is generally available, and PBIR is now the default report format. After that, the interesting work is in agentic authoring, a set of text-search features that are new to DAX, and a long list of reporting fixes.
Power BI Projects is generally available, and PBIR is the new default
Power BI Projects entered preview in 2023 and is now generally available. PBIP stores report and semantic model definitions as human-readable text files, which turns a Power BI solution into something closer to a codebase. You can search those files, track changes in Git, review diffs in pull requests, automate updates with scripts and pipelines, and point AI agents at models and reports. Changes stay visible and reversible, which makes team development easier and safer.
Two formats sit underneath it. Semantic models use the Tabular Model Definition Language, TMDL. Reports use the Power BI Enhanced Report Format, PBIR. The line that matters most: PBIR is now the default report format for PBIX and PBIP files. New reports use it from the start, and when you edit a report that uses the legacy format, Power BI tools convert it automatically.
That last point is why this is worth knowing even if you never open a PBIP folder. The format change reaches ordinary PBIX files, not just projects. Microsoft also highlights two recent workflow improvements that shipped in August: opening a project directly in Visual Studio Code, and Desktop detecting external file changes so you can edit outside the application and reload without restarting.
Dark themes and one ribbon for report styling
The Design ribbon is generally available and pulls report styling into a single place. From it you can apply a built-in or organizational theme, open the Theme pane to customize report-wide defaults, and import or download theme files. It also gives quick access to Page size, Page background, and Wallpaper for the current page.
Two new built-in themes arrived with it, Dark and Soft dark. Both use a new color palette called Versa, and their styling closely follows the Fluent 2 base theme that new reports have started on since August. Microsoft notes you can design against a dark report canvas and return to the default light theme before publishing, so working in dark mode does not commit you to shipping in it.
This is the third consecutive month of theming work: the customize-theme panel in preview in July, generally available in August with the font overrides removed from the base theme, and now a ribbon and two dark themes.
Agentic authoring and what is actually available
Power BI Agentic Experiences reached general availability. The model is that a developer delegates work to an agent, reviews the result, and refines it, rather than starting from scratch each time. Microsoft's argument for why this works is context: the agent grounds itself in your data and semantics through Fabric IQ and Work IQ, and picks up your team's modeling and reporting conventions through skills, which Microsoft publishes in a public repository, the community shares, and individual teams personalize.
Four pieces are named as available today. A powerbi-authoring plugin bundles the semantic modeling and reporting skills and tools, recently updated to support report authoring against remote semantic models in the service and a wider range of visuals, including custom visuals. A local Power BI Authoring MCP server lets an agent edit semantic models in Desktop. A Power BI Desktop Bridge lets an agent reload its changes in a running Desktop instance and capture screenshots to check its own work. And browser-based validation lets the agent validate a report through a headless browser, which removes the local Desktop dependency and extends the loop to Mac users and anyone without a local install.
A remote Power BI Authoring MCP server is also in preview, creating and modifying semantic models in Fabric workspaces with nothing installed locally. The local server, released in November 2025, stays generally available and remains the right choice when an agent needs to work with Desktop, PBIP or TMDL files on disk.
Copilot spreads out and gets a governance switch
Several Copilot items shipped alongside the agentic work. Power BI data answers in Microsoft Copilot Chat is generally available, so users can search for Power BI content, attach a report or paste a link, and ask questions in natural language, grounded in the measures, relationships and business logic already defined in the model. Microsoft 365 Copilot now supports Purview Data Loss Prevention policies and information protection controls for this experience, and existing Power BI permissions still apply. The Fabric IQ plugin in Microsoft 365 Copilot Cowork is also generally available, with responses citing the Power BI content behind an answer and surfacing its sensitivity label.
Microsoft 365 Copilot integrated directly into Power BI and Fabric is in preview. It is controlled by a new Fabric admin portal setting that is off by default, and during the initial preview it is available only to users with a Microsoft 365 Copilot license. Separately, viewing a report now lets you enable Fabric IQ from the Copilot pane for multi-step reasoning, which can show its reasoning steps, generate visuals, and surface the underlying DAX query behind a response.
The item most worth knowing about if you administer content is quieter. Semantic model editors can now block read-only users from reaching a model through Copilot and Microsoft's remote MCP tools. The setting applies across Power BI Copilot, Microsoft 365 Copilot Chat and Cowork, data agents, and the Fabric and Power BI MCP servers, and it stays enabled by default to preserve current behavior. If you have held back on AI access for governance reasons, that is the control.
Text search comes to DAX
Three modeling previews target performance, and two of them change what DAX can do with text.
APPROXIMATEDISTINCTCOUNT already worked against DirectQuery sources such as Azure SQL, Synapse, BigQuery, Databricks and Snowflake. It now extends to Import, Direct Lake on OneLake, and Direct Lake on SQL. Instead of scanning every unique value it estimates, with a standard error of about 1.6%, in exchange for faster queries. Microsoft's guidance is to use it on high-cardinality columns such as transaction IDs, user IDs or timestamps, and to keep exact DISTINCTCOUNT for low-cardinality attributes like Country or Status, and for financial metrics where precision is required.
String Indexing builds specialized indexes so the engine can locate matching text more efficiently, which helps common operations like SEARCH and CONTAINSSTRING and text slicers on large models. It offers an Auto mode that builds the index in memory on first query, and a Full mode that builds and persists it during scheduled refreshes at some cost to refresh time and model size. It requires compatibility level 1707 and, during preview, is configured through TMDL on the web or XMLA metadata.
Full-Text Search goes further, indexing for meaning rather than character matches, and introduces two DAX functions. TEXTCONTAINS returns TRUE when text matches a search expression using full-text semantics, supporting keyword, phrase and fuzzy matching. TEXTSIMILARITY returns a relevance score, so you can rank records by how well they match a phrase even when the words differ. It handles word forms, singular and plural variants, stop words and minor spelling mistakes. It requires compatibility level 1708 and is likewise configured through TMDL or XMLA during preview. If your model holds customer feedback, support tickets or product descriptions, this is the one to watch.
More of Power BI moves into the browser
DirectQuery semantic models can now be created and edited directly in the Power BI service, without downloading Desktop. You can connect to a supported source and choose DirectQuery mode, open existing models to manage relationships, write DAX and adjust table and column properties, and switch table storage modes between DirectQuery, Import and Dual. Composite models are available on the web as a result. It also means Mac and Linux users can author these models from the browser, and several people can work on the same model at once.
The report ribbon has come to the web in preview, organizing commands into tabs that more closely match Desktop and bringing across capabilities that were not previously available in the browser, including Format Painter and the new Design ribbon. You enable it with a Try the new ribbon setting at the top of the page and can switch back.
The new Power Query editor is also in preview, following the modern Get Data experience that arrived in May. It brings a consistent dark theme across the editing surface, step folding indicators and a query plan so you can see where folding breaks down, a diagram view for tracing how queries relate, and capabilities that previously only existed on the web such as rank column, cluster values and schema view. You can also export a Power Query template from Desktop and import it into a Dataflow Gen2. Enable it under Options, Preview features, New Power Query experience.
A Microsoft Outlook Mail connector is in preview too, built on the Graph API, reading folders, messages and attachments with an organizational account. It is the first of a planned set replacing the Exchange Online connector. Scheduled refresh is not supported yet, in the service or through the on-premises gateway, which limits it to exploration for now.
Reporting fixes worth knowing
Categorical axes can open on the most recent data. Set Initial scroll position to End in the axis Layout section and the visual loads at the end of the data instead of the beginning. It covers stacked, clustered and 100% stacked bar and column charts, line, area, stacked area and 100% stacked area charts, the line-and-column combo charts, and ribbon, waterfall and scatter charts with a categorical X-axis.
Export to Excel from table visuals using Data with current layout now supports up to 500,000 rows, raised from 150,000.
Report viewers can right-click a column header in a table or matrix and set its width in pixels, then reset it. Viewer changes last only for the current session and do not affect the author's design or other viewers.
Expanded section headers stay pinned at the top of the Format visual pane as you scroll, so you can see which section you are editing.
Visual calculations now work in visuals with small multiples. The small multiples field appears on the ROWPAGES axis, which you can use alone or combine with ROWS and COLUMNS to control how a calculation moves through the visual.
Power BI Home gained Data Refreshed and Modified Date columns, plus Column Options for showing, hiding and reordering metadata.
Slicers picked up slider color options across the Between, Before, After and Date picker settings, with handle styles that change depending on whether Responsive layout is on.
On-object interaction improvements in preview: the Build flyout now opens only when you select Add data, and Title and Subtitle are managed separately. Title and subtitle are now off by default for matrix, table and card visuals in reports using the latest base theme; existing reports pick this up via Update theme in the Theme pane.
Azure Maps re-evaluates reference layer features whenever report filters are applied, so filtering to a smaller area now shows the relevant features. The unfiltered view is still capped at 30,000 features.
The Narrative visual replaces its Q&A-based value creation with a deterministic UI where you pick a column or measure, apply a summarization and add filters. This follows the announced retirement of the Q&A tool. Auto-generated values are unchanged and values previously authored with Q&A remain available as read-only.
Translytical task flow buttons now display the assigned Workspace, Function set and Data function as read-only details in the formatting pane.
In the mobile apps, contact details now appear in the Info drawer for reports, apps and dashboards, so you can email the relevant contact from your phone.
Power BI content in Microsoft Teams tabs now shows an artifact info header with the name, sensitivity label and an entry point to metadata. Tab owners can turn it off.
Two things to act on
The file picker deadline has arrived. Microsoft's notes say that starting in October, anyone running a March 2026 or earlier build of Power BI Desktop can no longer save and share Power BI files to OneDrive and SharePoint. We are in October now, so this is no longer something to plan for. If anyone on your team is still on an older build, that is this week's job, and keeping Desktop updated is the whole fix.
Power BI subscription emails are also moving to a new delivery platform. Subscriptions transfer automatically and do not need recreating, but the sender identity and email formatting may change. If your organization filters or routes subscription emails by sender, flag it to whoever maintains those rules before the change reaches you.
What I would do first
Check what format your reports are in, because PBIR now applies to ordinary PBIX files and not just projects. If you have wanted version control on Power BI work and found PBIP too early to commit to, general availability is the moment to revisit it. Try the Dark theme on your next build, since it costs nothing and you can switch back before publishing. And if your model holds a lot of text, read up on Full-Text Search now so you are ready when it leaves preview.
How we think about this at Eigen X
We track every Power BI and Fabric release so the teams we work with can spend their time building instead of reading changelogs. If you want a hand turning any of this into cleaner reports, better models, or a distribution setup that scales, get in touch through eigenx.com. And if you want the monthly rundown as it happens, the series runs on LinkedIn.
