On 16 Mar 2017, Guile 2.2.0 was released with a new optimizing compiler and high-performance register virtual machine. According to the release announcement by Andy Wingo, real-world programs often showed a speedup of 30% or more with Guile 2.2 when compared to the previous 2.0 series. Guile 2.2.0 also lowered memory usage, sped up the "eval" interpreter, provided better support for multi-core programming, and removed any fixed limit on recursive function calls. It also supported the creation of user-space concurrency facilities that multiplex millions of concurrent lightweight "fibers" and provided a complete Emacs-compatible Elisp implementation, implementing all of Elisp's features and quirks in the same way as Emacs.