I'm fine waiting until the next release to officially move to Java 25. If the existing PR is merged to develop asap, that's exactly what will happen. And folks running Fineract can always decide to wait for the next release if they choose, providing them an even longer migration window.
But I'm not convinced they'll need one. Containers are the most popular deployment/dependency bundling/resource segregation mechanism today, and changing from a Java 21 base image to a Java 25 base image is a one-line patch. Long-lived branches are a bad idea. The work is pretty much done and I'm strongly in favor of proceeding asap. This helps development speed and likely runtime speed+safety as well. There's no FSIP. I don't believe we need one for this.
