New features
- Add out-of-sample predictions (`predictions` and `predictions_constant_data` groups) to pymc3, pystan, cmdstan and cmdstanpy translations ([983](https://github.com/arviz-devs/arviz/pull/983), [1032](https://github.com/arviz-devs/arviz/pull/1032) and [1064](https://github.com/arviz-devs/arviz/pull/1064))
- Started adding pointwise log likelihood storage support ([794](https://github.com/arviz-devs/arviz/pull/794), [1044](https://github.com/arviz-devs/arviz/pull/1044) and [1064](https://github.com/arviz-devs/arviz/pull/1064))
- Add out-of-sample predictions (`predictions` and `predictions_constant_data` groups) to pymc3 and pystan translations ([983](https://github.com/arviz-devs/arviz/pull/983) and [1032](https://github.com/arviz-devs/arviz/pull/1032))
- Started adding pointwise log likelihood storage support ([794](https://github.com/arviz-devs/arviz/pull/794), [1044](https://github.com/arviz-devs/arviz/pull/1044))
- Violinplot: rug-plot option ([997](https://github.com/arviz-devs/arviz/pull/997))
- Integrated rcParams `plot.point_estimate` ([994](https://github.com/arviz-devs/arviz/pull/994)), `stats.ic_scale` ([993](https://github.com/arviz-devs/arviz/pull/993)) and `stats.credible_interval` ([1017](https://github.com/arviz-devs/arviz/pull/1017))
- Added `group` argument to `plot_ppc` ([1008](https://github.com/arviz-devs/arviz/pull/1008)), `plot_pair` ([1009](https://github.com/arviz-devs/arviz/pull/1009)) and `plot_joint` ([1012](https://github.com/arviz-devs/arviz/pull/1012))
- Added `transform` argument to `plot_trace`, `plot_forest`, `plot_pair`, `plot_posterior`, `plot_rank`, `plot_parallel`, `plot_violin`,`plot_density`, `plot_joint` ([1036](https://github.com/arviz-devs/arviz/pull/1036))
- Add `skipna` argument to `hpd` and `summary` ([1035](https://github.com/arviz-devs/arviz/pull/1035))
- Added `transform` argument to `plot_trace`, `plot_forest`, `plot_pair`, `plot_posterior`, `plot_rank`, `plot_parallel`, `plot_violin`,`plot_density`, `plot_joint` ([1036](https://github.com/arviz-devs/arviz/pull/1036))
- Add `marker` functionality to `bokeh_plot_elpd` ([1040](https://github.com/arviz-devs/arviz/pull/1040))
- Add `ridgeplot_quantiles` argument to `plot_forest` ([1047](https://github.com/arviz-devs/arviz/pull/1047))
- Added the functionality [interactive legends](https://docs.bokeh.org/en/1.4.0/docs/user_guide/interaction/legends.html) for bokeh plots of `densityplot`, `energyplot`
and `essplot` ([1024](https://github.com/arviz-devs/arviz/pull/1024))
- New defaults for cross validation: `loo` (old: waic) and `log` -scale (old: `deviance` -scale) ([1067](https://github.com/arviz-devs/arviz/pull/1067))
- **Experimental Feature**: Added `arviz.wrappers` module to allow ArviZ to refit the models if necessary ([771](https://github.com/arviz-devs/arviz/pull/771))
- **Experimental Feature**: Added `reloo` function to ArviZ ([771](https://github.com/arviz-devs/arviz/pull/771))
- Added new helper function `matplotlib_kwarg_dealiaser` ([1073](https://github.com/arviz-devs/arviz/pull/1073))
- ArviZ version to InferenceData attributes. ([1086](https://github.com/arviz-devs/arviz/pull/1086))
- Add `log_likelihood` argument to `from_pymc3` ([1082](https://github.com/arviz-devs/arviz/pull/1082))
- Integrated rcParams for `plot.bokeh.layout` and `plot.backend`. ([1089](https://github.com/arviz-devs/arviz/pull/1089))
- Add automatic legends in `plot_trace` with compact=True (matplotlib only) ([1070](https://github.com/arviz-devs/arviz/pull/1070))
- Updated hover information for `plot_pair` with bokeh backend ([1074](https://github.com/arviz-devs/arviz/pull/1074))
Maintenance and fixes
- Fixed bug in density and posterior plot bin computation ([1049](https://github.com/arviz-devs/arviz/pull/1049))
- Fixed bug in density plot ax argument ([1049](https://github.com/arviz-devs/arviz/pull/1049))
- Fixed bug in extracting prior samples for cmdstanpy ([979](https://github.com/arviz-devs/arviz/pull/979))
- Fix erroneous warning in traceplot ([989](https://github.com/arviz-devs/arviz/pull/989))
- Correct bfmi denominator ([991](https://github.com/arviz-devs/arviz/pull/991))
- Removed parallel from jit full ([996](https://github.com/arviz-devs/arviz/pull/996))
- Rename flat_inference_data_to_dict ([1003](https://github.com/arviz-devs/arviz/pull/1003))
- Violinplot: fix histogram ([997](https://github.com/arviz-devs/arviz/pull/997))
- Convert all instances of SyntaxWarning to UserWarning ([1016](https://github.com/arviz-devs/arviz/pull/1016))
- Fix `point_estimate` in `plot_posterior` ([1038](https://github.com/arviz-devs/arviz/pull/1038))
- Fix interpolation `hpd_plot` ([1039](https://github.com/arviz-devs/arviz/pull/1039))
- Fix `io_pymc3.py` to handle models with `potentials` ([1043](https://github.com/arviz-devs/arviz/pull/1043))
- Fix several inconsistencies between schema and `from_pymc3` implementation
in groups `prior`, `prior_predictive` and `observed_data` ([1045](https://github.com/arviz-devs/arviz/pull/1045))
- Stabilize covariance matrix for `plot_kde_2d` ([1075](https://github.com/arviz-devs/arviz/pull/1075))
- Removed extra dim in `prior` data in `from_pyro` ([1071](https://github.com/arviz-devs/arviz/pull/1071))
- Moved CI and docs (build & deploy) to Azure Pipelines and started using codecov ([1080](https://github.com/arviz-devs/arviz/pull/1080))
- Fixed bug in densityplot when variables differ between models ([1096](https://github.com/arviz-devs/arviz/pull/1096))
Deprecation
- `from_pymc3` now requires PyMC3>=3.8
Documentation
- Updated `InferenceData` schema specification (`log_likelihood`,
`predictions` and `predictions_constant_data` groups)
- Clarify the usage of `plot_joint` ([1001](https://github.com/arviz-devs/arviz/pull/1001))
- Added the API link of function to examples ([1013](https://github.com/arviz-devs/arviz/pull/1013))
- Updated PyStan_schema_example to include example of out-of-sample prediction ([1032](https://github.com/arviz-devs/arviz/pull/1032))
- Added example for `concat` method ([1037](https://github.com/arviz-devs/arviz/pull/1037))