Robot Framework 6.0 is a new major release that starts Robot Framework's localization efforts. In addition to that, it contains several nice enhancements related to, for example, automatic argument conversion and using embedded arguments. Robot Framework 6.0 rc 1 is the first and hopefully also the last release candidate containing all features and fixes planned to be included in the final release.
Robot Framework 6.0 was initially labeled Robot Framework 5.1 and considered a feature release. In the end it grow so big that we decided to make it a major release instead.
For more details see the [full release notes](https://github.com/robotframework/robotframework/blob/master/doc/releasenotes/rf-6.0rc1.rst).