Matlab upgraded to HDF5 1.8.12 in R2015a and Matlab is still at HDF5 1.8.12 at least through R2019b. This means to ensure interoperability with files from h5py and other such HDF5-using software, one should currently use HDF5 1.8 files. Newer versions of the HDF5 library (e.g. 1.10) can write HDF5 1.8 files. HDF5 1.8.12 was released in November 2013. HDF5 1.8.21 was released inJune 2018and is perhaps the last HDF5 1.8 release.
Matlab R2019b shows HDF5 1.8.12 is used:
[majnum,minnum,relnum] = H5.get_libversion()