The central aspect of upcoming DMX 5.0-beta-2 is consolidating the database, so that subsequent releases can be installed without the need for data migration. Data stored in 5.0-beta-2 is save.
Besides the standard application models, which are addressed separately in #89 (closed), this ticket addresses the lower (meta) levels of the data model like e.g. types, view configs, topicmaps.
The release of DMX 5.0-beta-2 is scheduled for Apr 2019.
The subject of the DMX 5.0-beta-2 milestone is database consolidation, not API consolidation, which will be the subject of the final DMX 5.0 release.