And the releases will be build using the lowest supported Java version
With the --release flag in our hands from JDK 9 onwards, maybe we could switch to JDK 10 (and later 11), with the release flag set to Java 7. This would allow Spock to be build with a current JDK in a backwards-compatible way while still having builds with all officially supported JDKs.
animal sniffer should probably be added as well