Hyperlinked release notes can be found here:

file:///home/tom/fias/lib/pypsa/doc/_build/html/release_notes.html#pypsa-0-15-0-8th-november-2019

This release contains new improvements and bug fixes.

* The unit commitment (UC) has been revamped to take account of
  constraints at the beginning and end of the simulated snapshots
  better. This is particularly u seful for rolling horizon UC. UC now
  accounts for up-time and down-time in the periods before the
  snapshots. The generator attribute initial_status has been replaced
  with two attributes up_time_before and down_time_before to give
  information about the status before network.snapshots. At the end of
  the simulated snapshots, minimum up-times and down-times are also
  enforced. Ramping constraints also look before the simulation at
  previous results, if there are any. See the unit commitment
  documentation for full details. The UC example has been updated with
  a rolling horizon example at the end.
* Documentation is now available on readthedocs, with information
  about functions pulled from the docstrings.
* The dependency on cartopy is now an optional extra.
* PyPSA now works with pandas 0.25 and above, and networkx above 2.3.
* A bug was fixed that broke the Security-Constrained Linear Optimal
  Power Flow (SCLOPF) constraints with extendable lines.
* Network plotting can now plot arrows to indicate the direction of
  flow.
* The objective sense (minimize or maximize) can now be set (default
  remains minimize).
* The network.snapshot_weightings is now carried over when the network
  is clustered.
* Various other minor fixes.

We thank colleagues at TERI for assisting with testing the new unit
commitment code, Clara Büttner for finding the SCLOPF bug, and all
others who contributed issues and pull requests.