ESPResSo 4.2.0 feature freeze

[Jean-Noël Grad]

Dear ESPResSo users and contributors,

The ESPResSo team is happy to announce the development version on GitHub 
has reached the stability threshold necessary for a 4.2.0 release. We 
planned a feature freeze on the 15th of April and an official release in 
May of this year.

We warmly invite you to try out the python branch in April and report 
any build issue that is not already addressed in the installation FAQ 
[1]. We would also like to hear about any software bug you may encounter 
while porting your simulation scripts to the python branch. Several API 
changes will break 4.1.4 scripts, in particular: the global random 
number generator was removed, particle access via `system.part[i]` is 
now done via `system.part.by_id(i)`, reaction methods now take keyword 
arguments and the ELC actor now takes a P3M actor as argument. A 
complete list of API changes is available in [2]. We recommend building 
the development branch in a new build folder to avoid issues with Cython 
ImportError [3].

The ESPResSo team and the ESPResSo community have been busy preparing 
the next software releases over the last 18 months. The 4.2.0 release 
will replace the aging 4.1.4 release with many quality-of-life 
improvements and new features, such as breakable and reversible bonds, 
Lees-Edwards boundary conditions, Stokesian Dynamics and Brownian 
Dynamics. The 4.3.0 release will ship with a brand new lattice-Boltzmann 
framework based on waLBerla [4] and a new diffusion-advection-reaction 
solver for modelling electrokinetics and catalysis. The development 
version of 4.3.0 will become the python branch soon after 4.2.0 is released.

Best regards,
Jean-Noël Grad

Links:
[1] https://github.com/espressomd/espresso/wiki/Installation-FAQ
[2] 
https://github.com/espressomd/espresso/wiki/es-420-release-notes#interface-changes
[3] 
https://github.com/espressomd/espresso/wiki/Installation-FAQ#Import_errors_due_to_missing_symbols
[4] https://walberla.net