I fought (and lost) for java 8 usage in the spring-boot extension. Long discussion, essence camunda platform is java6, extensions should use 6 as well … 7 if there is no other way.
Now a new star rose on the extension sky: camunda-bpm-mail. And it uses … java 8.
May I interpret this as an official end to the “stick to java6” rule for extensions. Then I would switch spring boot as well.