**The 4.1.x series is the last to support Python 2.7 and Python 3.5. From 4.2.0 onward, only Python 3.6 and above will be supported.**
(Any bug-fixes that absolutely must be used in an old Python environment will need to be versions 4.1.10, 4.1.11, etc., and these won't include features and regular maintenance that go into the main branch, 4.2.x and beyond.)
In this version:
pfackeldey removed an unnecessary copy of memory-mapped data.
veprbl exposed the `data` property of TTable: PR 506.
jpivarski added an example of RNTuple header parsing: accidentally as 4bb0f6aedbe7e9a8ba8feb166a16e71274259d26, rather than a formal PR. Added more careful DataFrame-checking code in TTree-writing, to avoid a spurious error message: PR 517. Fixed a picking issue with histograms (just the TAxis) by ensuring that all Behaviors are not Python Abstract Base Classes: PR 521.