**Change in the Xsuite package structure:**
- The xline package is removed
- xline.Line becomes xtrack.Line
- instead of xline.Drift, xline.Multipole etc. use directly xt.Drift, xt.Multipole
- The Tracker objects are automatically updated when the line is modified (no need to regenerate the tracker)
- There is only one Particles class within Xsuite
- xline.Partices and xtrack.Particles to be replaced by xpart.Particles
- The reference python implementation of the main elements, which used to be in xline, is moved to a small package called ducktrack, installed together with xtrack, to be used only for testing purposes (not part of normal tracking workflow)
**New features**
- Added build_particles function allowing to build a particles object from a reference particles plus arrays with geometric or normalized coordinates
- Added tools to compute and symplectify one-turn matrices (moved from pymask)
- Random number generator moved from xtrack togehter with the Particle class
- Ported PyHEADTAIL interface from xtrack