Hello,
The Wikimedia Jenkins system now uses NodeJS version 6 (was 4).
That is part of a plan to upgrade the Wikimedia cluster to 6 which is tracked on: https://phabricator.wikimedia.org/T149331
If you see any issue with the *node-6-jessie Jenkins jobs, please fill them as sub tasks of T149331 and add in #contint Phabricator project.
Thanks Paladox for the CI configuration change and everyone that has been involved in ensuring our most important softs are compatibles.