Check the server version before following an old menu path
A missing Next Up (Legacy) section after a layout change does not by itself mean episode history was erased. Emby’s current Home Screen guide distinguishes server 4.10.x from the earlier 4.8.x and 4.9.x interface. Establish which version you are configuring and whether the expected items can still be found in their television library.
Build the section with the current controls
The 4.10.x guide recreates a next-up view using a Continue Watching home section. Give it the desired title, select the intended TV libraries and enable Include next up episodes in Continue Watching. The documentation explains that some older library-level inclusion preferences moved into per-section library selections. It also warns that newly added libraries are included in home sections with selected libraries, so revisit those selections after adding a library that should stay out of this particular view.
Verify the section rather than rearranging storage
For example, a household may want one next-up row for dramas and a separate row for a documentary library. Check the selected libraries and next-up option on each section, then inspect a series with a known next episode. A wrong row membership calls for a home-section check before moving files between storage folders. Keep presentation separate from permissions: choosing libraries for a home row describes that row, while account access remains a separate configuration. Record the section type, library selection and observed episode when asking for help, so a changed layout can be assessed without assuming the media or viewing history disappeared.
Questions, answered
Where did Next Up (Legacy) go in the documented 4.10.x setup?
The guide recreates it with a Continue Watching section and its option to include next-up episodes.