The next release (2.3.0) is a rather large release and includes numerous new features as well as a huge amount of bugfixes. The milestones on Github (see links provided by Tgtje) give insight in what currently is still open. Once those are fixed, we are close to a release.
Additionally, we have also implemented automated testing in Github recently, which took quite some time, and we are writing new tests for it to get the coverage percentage (the amount of code that is automatically tested) up.
I cannot give you any expected due date, as I am pretty sure we won't stick to it. The developers are all volunteers with full-time jobs and families to take care of at the same time. You can test the latest version and provide feedback by using the latest files on Github. Please be aware that this version may contain bugs, so be sure to make backups if you apply the latest files on a live installation.