Migration is a one-time pass per object. Plan a fresh field-set design rather than copying the Mini Page Layout directly.
- Inventory existing Mini Page Layouts
Setup, Object Manager, each object, Page Layouts, find the Mini Page Layout configuration. Document the field sets per record type.
- Identify the per-object Compact Layout
Setup, Object Manager, the object, Compact Layouts. Open or create the layout.
- Pick the right field set for Lightning
The Compact Layout drives Highlights Panel, mobile, search, and hover. Pick fields that work across all these surfaces, not just the hover popup.
- Assign per record type
Use Compact Layout Record Type Assignments to map each record type to the appropriate Compact Layout.
- Verify in Lightning
Switch to Lightning Experience. Verify the Highlights Panel, hover preview, and search results all show the expected fields.
- Skip Mini Page Layout updates going forward
Once Lightning is the active UX, Mini Page Layout edits do nothing. Update Compact Layouts only.
- Mini Page Layouts are Classic-only. They do nothing in Lightning Experience.
- Compact Layout drives more surfaces than Mini Page Layout did. Picking the wrong field set affects mobile and search, not just hover.
- Migration is a one-time pass per object. Plan a fresh design rather than copying field sets blindly.
- Documentation drift is severe. Treat any Salesforce article older than 2018 referencing Mini Page Layouts as historical context.