FME Desktop 2021 into FME Form 2025

A few things to consider:

1. Running a 2021 workspace in 2025 will result in performance improvements (to what degree may vary depending on what transformers are being used)
2. Further performance improvements can be gained by subsequently upgrading the transformers.
3. In 2025 transformer upgrading is really easy as you can upgrade all instances of a transformer at once.
4. The above is also very risky as there may be some behavior changes between the different versions. It is very important to thoroughly test workspaces after they’ve been upgraded.
5. Don’t forget about upgrading readers and writers
6. The jump from 2021 to 2025 is pretty massive, you’ll find a wide range of new and improved transformers. Upgrades like this are often good opportunities to revist processes and see if:
   1. New transformers (functionality) can be leveraged
   2. Tech debt in existing process can be resolved
   3. New ways of achieving the outcome can be explored
7. You will also find that over that time period Python has evolved. any Python will need to be upgraded from 2.7 to 3.x. Again, some of this Python could be replaced by transformers
8. If you’re working with Esri, make sure you maintain compatibility across the platforms - https://support.safe.com/hc/en-us/articles/25407724093837-Notes-on-FME-and-Esri-Versions-and-Compatibility

Agree with ​@hkingsbury and would like to point out the obvious: start upgrading the most often used workspaces first. There’s a good chance you will see performance increase there.