Does TPE use True north or Magnetic North?

All versions of TPE (The Photographer's Ephemeris) show azimuths and bearings relative to true north.

TPE for IOS

Our iOS app has a setting to use Magnetic North instead. This is rarely required unless you are using a field compass which has not been offset for local magnetic declination. If you're uncertain, or you're not using a field compass, we recommend leaving this setting off.

When enabled, the app will display all numerical azimuths as measured relative to magnetic north. The magnetic declination (i.e. the difference between true and magnetic north, in degrees) is determined automatically based on the red (primary) pin location and the selected date. TPE uses the World Magnetic Model to determine this. At the time of writing, TPE 4.5.3 uses WMM2015b (the current version).

Note: enabling magnetic north has no effect on how the azimuth lines are drawn on the map. Changing a setting doesn't change where the sun will rise ;)