Interchange

Your programme is someone else's file.

The main contractor issues P6. The client wants MS Project. A subcontractor sends a spreadsheet. Nobody is changing tools because you did. A scheduler that cannot read those files is a scheduler you keep a second licence alongside — so LumaPlan reads them directly, and writes them back.

Formats

What it opens, and what it writes.

FormatFromReadWriteNotes
.mppMS ProjectYesOpens directly — no export step first. MPP9 through MPP14.
.mspdi / .xmlMS ProjectYesYesRound-trips through MS Project itself, field for field.
.xerPrimavera P6YesYesThe format the industry actually exchanges.
.pmxmlPrimavera P6YesYesThe XML variant, for tools that prefer it.
.mpxExchangeYesYesThe old lingua franca, still in the chain more often than people admit.
.xlsxExcelYesYesImport a task list; export rows, resources or the current view.
.lplanLumaPlanYesYesThe native file. Round-trips everything the other formats drop.

Out the other side: PDF submittals with a timescaled Gantt, a what-you-see print of the current view, XLSX, PPTX, PNG and SVG.

Conventions

MS Project and P6 do not agree on dates.

They differ on whether a finish is inclusive, how lag is counted across a non-working span, and whether a zero-duration activity gets promoted to a milestone. Feed the same logic to both and you get answers a day apart — which is exactly the argument nobody wants to be having in a progress meeting.

LumaPlan implements both conventions and makes the project choose. Import a P6 file and it schedules the way P6 does. Import from MS Project and it schedules the way MS Project does. The setting is visible in project settings, not inferred and hidden.