The September Licensing Guides…

Microsoft published the September 2026 licensing guides for Dynamics 365, Power
Platform, and Copilot Studio. I pointed Claude at the PDFs and asked it to update the
pricing catalog inside the D365 F&SCM Cost Estimator.

Every currency and GB figure came back identical to the August edition. The “Default
subscription capacity included per tenant” appendix was byte-identical. Nothing moved.

That is a useful answer, and it is not one you can get without doing the work.
**The output of a pricing pass is not new prices. It is a verified date.**

What did change

Dynamics 365 Headless Commerce reached general availability, and it brings two add-ons:
Headless import and Headless orchestration. Each includes 30,000 retail transactions per
month plus one Commerce Scale Unit (Cloud), with overage at 5,000 per month, enforced
annually in aggregate.

Microsoft prints no price for either one, and neither appears on the August 24 NCE price
sheet. So both sit in the catalog as documented $0 placeholders, unreferenced by the
engine and not shown in the UI. Wiring up the transaction mechanics is a separate change.
I would rather ship a placeholder with a note than a number I made up.

Why re-verify when nothing moves

On a previous pass I fed the tool a Power Platform licensing guide I believed was a month
old. It was 13 months old. The figures I used from it had not changed since, so no
estimate I produced was wrong. That was luck, not process.

A stale source is exactly the failure mode a verification pass catches, and it never
announces itself. The file opens, the numbers look plausible, and you move on.

The mistake that cost the most

It was not the prices. I decided to rename the catalog from `pricing.v2026-08.json` to
`pricing.v2026-09.json` so the verification date would be visible without diffing.

That happened to cost a lot of time, because every file referencing the old name had to change with
it: the app itself, three Cowork reference files, and the front matter in the tests. One
decision about a file name turned a single-file edit into a spread of changes and a longer
test cycle.

The fix is the one you would apply to any constant. Give the file a generic name that
anything can reference, and record the verification date in the data, where it belongs.

What the run cost

92 tests passed. Over two hours of wall clock. On API credits instead of my subscription
it would have run about $13.

The two hours are on me. I ran the session in a mode that lets it edit files but not
execute commands, and it needed to run MarkItDown to convert the PDFs to Markdown and then
run the test suite. So it sat waiting on my approval. I was not watching it. Twice I came
back to find 15 minutes gone on a click I owed it.

For $13 and almost none of my attention, that is still a trade I will take. But the
deterministic half of this belongs in a Python script, and that is where I am putting it.

If you use the estimator

Prices load from the defaults, so open Settings, hit **Set defaults**, then create a new
estimate and load your saved file. The tool is a single self-contained HTML file with no
server and no telemetry: https://github.com/dodiggitydag/d365-cost-estimator

I built it to answer the total cost of ownership question, whether you are budgeting a new
implementation or you are already ten years into Dynamics 365 and trying to work out what
next year looks like with the AI and licensing changes… and where to push when the EA
comes up for renewal.

https://youtu.be/jDCWY68HB8E

How are you using the estimator?