Tulip 5.2.1 is only a maintenance release.
It contains minor bug fixes noticely in the Import CSV and Export SVG plugins.
The support of Python 3.7 has been added. So the Tulip python wheels are now available for Python 2.7, 3.4, 3.5, 3.6 and 3.7 versions.
Important notice for Python users:
Tulip 5.2.1 is the last release with support of the tulipgui python module.