LibreOffice 6.0 Is In Development
LibreOffice 5.4 continues pushing forward and since last month LibreOffice 5.5 was then the version on Git master with the v5.4 code having already been branched. But now LibreOffice 5.5 will be LibreOffice 6.0.
The Git commit this morning indicates the next version is now LibreOffice 6.0 and not 5.5.
LibreOffice 6.0 is expected to introduce new branding and UI refinements and will be released in early 2018. More details forthcoming.