Dear all, The OONI team has been using the Measurement Kit <https://github.com/measurement-kit/measurement-kit> (MK) library since 2017 as its network measurement engine. Because every measurement run using MK by default also submits measurements to the OONI collector, we know that there are several people who have also integrated MK into their network measurement tools and apps. If you are one of those folks using MK, we’d like to thank you for using it and inform you that it is now deprecated. At OONI, we are now switching to a new engine <https://github.com/ooni/probe-engine> written in Go which will be easier for us to maintain in the long-term. We encourage you to consider adoption of the new Go probe-engine for your tools. We will keep maintaining MK for roughly one year and we will stop producing builds and applying fixes after March 14, 2021. We articulated an upgrade path in the new README of the Measurement Kit repo <https://github.com/measurement-kit/measurement-kit/blob/master/README.md> for all the MK use cases that we know of. If you have questions, comments, suggestions, or use cases that we didn’t consider, please let us know, either here or on GitHub <https://github.com/measurement-kit/measurement-kit/issues>. Thank you, best, Simone & the OONI team