Hey, I recently merged the new Flink UI [1]. After merging it, I was made aware that the frontend-maven-plugin requires at least Maven 3.1.0. There was a discussion about bumping the maven version already last year [2]. In that thread, Stephan mentions that some Linux distributions still have Maven 3.0.5 as their default version. Ubuntu 16.04 (the current LTS version) ships Maven 3.3.9. Debian Jessie (8) is indeed still shipping 3.0.5, Stretch (9) is on 3.3.9 too.
Given this situation, I propose to bump the required Maven version to 3.1.1. Flink releases are build with 3.2.5. If nobody raises any objections till Thursday, May 2nd, I'll open a PR bumping the version. Best, Robert [1] https://github.com/apache/flink/pull/8016 [2] https://github.com/apache/flink/pull/6443#issuecomment-410673911
