Frustrated by the censorship imposed by carriers on unencrypted SMS/MMS, as they refuse to send messages containing links to websites outside mainland China, and even worse, eventually blocking my SMS/MMS function, I have decided to no longer endorse the use of SMS/MMS.
SMS/MMS has long been the primary communication method for regular people who do not use free software instant messaging services like Matrix and Jabber. However, while SMS/MMS does not require non-free apps to use, the censorship and surveillance on SMS/MMS are no less than those on proprietary instant messaging services.
Unfortunately, I don’t know why, but the free software end-to-end encrypted SMS/MMS client Silence seems to have been discontinued—the official website is down, and the source code repository is no longer available. Despite the currently available app download from F-Droid, this makes the client harder to obtain and may encourage people to use non-free SMS/MMS apps without encryption enabled.