Ubuntu 16.04 LTS is still powered by the long-term supported Linux 4.4 kernel series, but when the Ubuntu 16.04.2 LTS point release was announced back in mid-February, four months after the release of Ubuntu 16.10 (Yakkety Yak), users were giving the possibility of installing the newer Linux 4.8 kernel of Ubuntu 16.10. But now that Ubuntu 16.10 reached end of life on July 20, 2017, it’s not safe to run its Linux 4.8 kernel anymore, as Canonical won’t provide security updates for it, so they’re now allowing Ubuntu 16.04.2 LTS users to install the much newer Linux 4.10 kernel from the Ubuntu 17.04 (Zesty Zapus) release.