Why is it not possible to update KODI by itself?
Because that's not the Recalbox philosophy. Recalbox is as plug an play as possible, and everything is tested before releasing to users.
When could we get an update in Recalbox?
We have a small team of developers who do as much as possible to fix bugs and make improvements, it is not possible to give release predictions until most of the tested changes are in place, when possible the release date is announced publicly, not in individual threads .
You can follow the changelog here:
https://gitlab.com/recalbox/recalbox/blob/master/CHANGELOG.md