New features
- The new `flavio.citations` module provides a bibliography of theory papers (thanks to MJKirk)
- At the end of a flavio computation, the theory papers on which the computation is based can be obtained from `flavio.citations.set` in terms of a set of INSPIRE citation keys. The bibliography can be reset by calling `flavio.citations.reset()`.
- The new `theory_citations()` method of the `Observable` class returns the theory papers on which the prediction of a given observable is based.
New observable
- The ratio of the branching ratio of B<sup>0</sup>→K*γ and the time-integrated branching ratio of B<sub>s</sub> →φγ, `BR(B0->K*gamma)/BR(Bs->phigamma)` (thanks to MartinoBorsato for the suggestion)
New measurements
- The B<sup>+</sup>→K*μμ angular observables by LHCb
- The combination of B<sub>s</sub>→μμ by ATLAS, CMS, and LHCb
- Some LEP measurement (thanks to MJKirk)
- Some LHCb and ATLAS measurements (thanks to olcyr)
Bug fixes
- Some bugs in the implementation of mu-e conversion have been fixed (thanks to xmarcano for reporting the issue)
- A problem with the PyYAML loader `SafeIncludeLoader` on some Windows systems has been fixed
Other improvements
- flavio now supports Python 3.9
- The PyYAML loader `SafeIncludeLoader` now supports absolute file paths in the `!include` and `!include_merge_list` constructors
- The config files have been updated to avoid matplotlib deprecation warnings (thanks to MJKirk)
- The interface to iminuit has been upgraded to use iminuit v2.x
End of support for Python 3.5
This release requires at least Python 3.6. Python 3.5 has reached [end-of-life](https://devguide.python.org/devcycle/#end-of-life-branches) on 30 September 2020. If you are on an outdated system and cannot update Python, have a look at [conda](https://docs.conda.io/). It allows you to install the newest version of Python in a virtual environment without root privileges. Conda is also the best choice if you are on Windows.