I don't have strong feelings on it, but I think I'd lean against it since we've already released artifacts under the 2.6 banner.
- It can be confusing when looking in somewhere like Maven Central that the already released 2.6 artifacts are in the same line as 2.9 (one might conclude without reading this thread that the 2.6 line was abandoned).
- If can affect other tooling that's already supporting 2.6, such as docker-groovy. If I'm using 2.6-jdk8 as a base for my images, I'll have to change to 2.9-jdk8 to continue getting the latest base
(or I guess I'll have to keep tagging all future 2.9s also as 2.6 just in case someone was doing that).