Dear all, We would like to make it easier for the community to see what is going on in terms of Kwant development. We hope that this will provide useful feedback and lower the barrier for participation. As a first step, we have created a new mailing list called “kwant-devel”. The new list will be used to discuss technical design and implementation issues of Kwant. The old list “kwant-discuss” will remain the place for general exchange about Kwant, Q&A, and bug reports. Over the next days we plan to discuss the design of an improved low-level system format for “kwant 2” on the new list. This new format should make the following possible: • Finalizing builders with more than a single translational symmetry vector. The additional symmetries could be used for periodic boundary conditions or multi-dimensional band structure calculations for example. • Better handling of parameters. Value functions should no longer be required to share the same parameters, and it should be possible to separately query the parts of the Hamiltonian that depend on a particular parameter. • Improved performance through vectorization of value functions. Low-level systems are at the core of Kwant. We would like to redesign them in a solid way and appreciate any feedback. If you would like to participate in the discussion (or just follow it), please subscribe to the “kwant-devel” at http://kwant-project.org/community. Everything works the same way as for the other lists (except that Gmane and Mail-archive do not just yet carry the new list). We hope to see many of you on kwant-devel. Christoph on behalf of the Kwant team