We are happy to announce the release of Brian 2.1. This release includes a number of fixes and small improvements, and two new major features: support for numerical integration with adaptive-timestep methods based on the GNU Scientific Library, and caching of code generation leading to faster simulation setup times, in particular for multiple runs of the same model. For an extensive list of changes, see the release notes. We recommend all users of Brian 2 to update. We also release a new version 1.1. of Brian2GeNN, Brian’s interface to the GPU-enhanced Neuronal Network simulation environment (GeNN). This release does not contain any major new features except for bug and compatibility fixes, but an update is required for all users that update to Brian 2.1. How to get Brian 2: follow the installation instructions in the documentation Further information about Brian2: http://brian2.readthedocs.org As always, please report bugs or suggestions to the github bug tracker or to the brian-development mailing list (brian-development@googlegroups.com).