The Windows 10 May 2019 is now available, just before the end of the month. That includes a new light theme, Windows sandboxing, and the uncoupling of Cortana and Search, among other features.
Users who want to update immediately can go to Settings > Update & Security > Windows Update and choose "Check for updates," then select "Download and install now."
Windows Insiders first saw the release last month, so we're hoping the issues have been worked out and we don't see problems like the ones that faced the October 2018 update. In the meantime, the April 2018 Update will reach end of service on November 12, 2019, for Home and Pro editions.
Also following the missteps in the October 2018 update, Microsoft is debuting a Windows release health dashboard that explains known issues for the rollout. Microsoft wrote that the feature would track issues "across both feature and monthly updates."