2026 Wave 1: Cleaning out the closet

PREAMBLE

(you may skip this section if you like, it is not technical, I am just thinking aloud)

A few months ago, I thought of creating a YouTube channel with chilling interviews of well-known member of the Dynamics 365 Business Central community and some of the clever minds in Lyngby. I also thought about a name: BC GoodFellas.

But what Brad Prendergast and Kristoffer Ruyeras are doing from the other side of the Ocean is super cool. I would encourage everyone subscribing to Dynamics Corner – YouTube. In the old continent, I would also follow Nils Peemoeller on LinkedIn and his interesting interview series.

BYO popcorn and hear about how people all over the world are connected altogether by the true love for this product.

Last but not least, I am pretty sure that when a What’s New in Dynamics 365 Business Central pops up, you directly jump into Yun Zhu’s blog as your first train stop and discover that it has been already dissected in tiny pieces. Chapeau.

And that is the reason why this blog: it is ahead of time. With a fast forward.

WHY

In these days we are all distracted by all the goodies provided in version 2023 Wave 2 (version 23) but Microsoft is already far ahead in time and set another big milestone that dictate the level of maturity and long term maintenance of its SaaS offering.

I am just echoing here the following official entry – that you might have overlooked -: Deprecated features in the client, server, database – Business Central | Microsoft Learn

Let me explain this in the easiest way possible.

1. Download one of the latest Base Application source code
2. Extract it and open it in Visual Studio Code
3. Search for “ObsoleteState = Removed”

What you have under your nose, it is the number of elements (Tables or Fields) that, currently, are lying around as useless ghosts in

1. Metadata schema in AL
2. Physically allocated space in the Environment (see Dynamics 365 Business Central: again about obsoleting fields – Stefano Demiliani)

“This is possible because none of the schema elements (tables and fields) deprecated over 11 major updates (from v.14 to v.25) were removed from the released databases to preserve backwards compatibility and enable more seamless transition for our customers to the latest versions on-premises and online.

Over these releases, we have accumulated a significant number of such obsolete schema elements, which increases complexity of working with the application code. This condition blocks the reuse of the long obsolete objects and field IDs, affecting our work of moving common functionality from local versions of Business Central to W1 version.”

WHAT

One of the developer FAQ about SaaS is:

“When will Microsoft get rid of all these OBSOLETE Table and Fields?”

These useless and stinky hanging fruits cannot last in there until the end of time.

Correct. Microsoft have finally a perfect long-term strategy.

WHEN

With 2025 Wave 1 (version 26), in April 2025, Microsoft will go through and clean up all schemas that have been marked as ObsoleteState = Removed since version 14. This will be the first “stepping-stone” release. And this cleaning activity will have a 5 major release cadence. This means roughly every 2.5 Years. The next will happen, then, with 2027 Wave 2 (version 30), in October 2027, and that will be the second stepping-stone release. And so on.

 (so) WHAT (?)

First consequence is that 2024 Wave 2 (version 25) will be the last one to support a direct upgrade from the hybrid version 14. Within on-premises, this means doing an intermediate upgrade to version 25. So that, the upgrade path will be:

• Pre-Version 14 to Version 14
• Version 14 to Version 25
• Version 25 to Version 26

And so on. Removing old schemas, means that also Cloud Migration should obey to that, and if you will be in need to take the leap to the cloud, since version 26 it will be mandatory to upgrade the database on-premises to the N stepping-stone versions, first.