CyanogenMod no longer supports WhisperPush, Signal app offered as alternative
Device security and data privacy have long been a part of CyanogenMod’s open-source, customizable and continuously improving Android vision, although running a CM nightly build can often be risky from a number of standpoints.
More so now that WhisperPush capabilities are disabled in Marshmallow-based CM13, unless you opt for the equally secure Signal app Edward Snowden himself commended in the recent past. In case you weren’t aware, WhisperPush was integrated into CyanogenMod starting way back in December 2013 to ensure your text messages were always encrypted and no outsider had access to your private communication.
But Signal apparently does that better, yielding none of the registration issues plaguing the CM user experience that WhisperPush caused, and it additionally encodes your voice calls too, combining TextSecure and RedPhone functionality.
Bottom line, this ending is literally a new beginning, and if you follow CM’s advice to install the Signal application on old and new devices running old and new CyanogenMod iterations, you’ll likely never have to worry about prying eyes and ears again.
All WhisperPush-registered numbers will be deactivated from the service no later than February 1, at which point your SMS messages shall lose their protection, unless shielded by Signal.
Source: CyanogenMod Blog