You can disagree all you like, but they lay out their policy here: https://support.signal.org/hc/en-us/articles/5109141421850-Supporting-Older-Operating-Systems

You can disagree all you like, but they lay out their policy here: https://support.signal.org/hc/en-us/articles/5109141421850-Supporting-Older-Operating-Systems https://support.signal.org/hc/en-us/articles/5109141421850-S... My guess would be that they want to dump the messy and easy-to-screw-up CommonCrypto code and switch fully to CryptoKit, which was introduced in ios 13. If you don't like their way of running their project, you have other options.