we added e2ee in beta in nov 2016 (https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-encryption-security-assessment-released-and-implemented-cross-platf

we added e2ee in beta in nov 2016 (https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-encryption-security-assessment-released-and-implemented-cross-platform-on-riot-at-last/ https://matrix.org/blog/2016/11/21/matrixs-olm-end-to-end-en...) and exited beta and enabled it by default in may 2020: https://matrix.org/blog/2020/05/06/cross-signing-and-end-to-end-encryption-by-default-is-here https://matrix.org/blog/2020/05/06/cross-signing-and-end-to-...