AprilTags can be used for loop closure (automatic single scene accuracy improvement by looping over unique tags multiple times) in any version of Dot3D with scanning capabilities enabled (Dot3D Scan, Dot3D X, and Dot3D Pro).
However, to use AprilTags for scale bar targeting (measured target-to-target distance references), hard targeting (known target coordinate references), or multi-scene stitching (via hard targeting), a Dot3D Pro (or Dot3D X) license is required. Dot3D Scan does not support this advanced targeting functionality.