We are pleased to announce the release of Siesta-4.0. This version should be the default choice for production for most users.
You can read the Release Notes and obtain the tarball in the release page.
Note in particular the BACKWARD COMPATIBILITY ISSUES and the TECHNICAL NOTES sections in the Release Notes for some important issues regarding backwards compatibility with 3.X versions and previous development snapshots.
See the file REPORTING_BUGS in the Docs/ directory of the distribution for instructions to report bugs and suggestions.