The Trustworthy Systems at Data61 (formerly NICTA) is pleased to announce seL4 release 4.0.0. The new release contains a number of new features, most notably the following: - support for the x64 platform - support for VT-x on the multicore ia32 platform - robustness improvements for handling device registers - API simplifications The full list is available at https://wiki.sel4.systems/seL4%204.0.0 We are also pleased to announce the first post at the new seL4 blog at https://research.csiro.au/tsblog/introducing-device-untyped-memory-sel4 Stay tuned for further posts on and around seL4. 2016 was an exciting year for seL4 with a lot of new developments, and great contributions from the community. We think that 2017 will be even better, with VT-x support for x64 in the pipeline, multicore support for ARM maturing, and formal verification for the x64 and ARM-hyp platforms scheduled to come out in the first half of the year. We’d like to thank everybody on this list for their support and enthusiasm. There are more cool things to come! Enjoy!