These allowed users to install the OS directly from their phone using a Custom Recovery or ClockworkMod.

This usually means the ZIP file is not compatible with your specific device model. Double-check your hardware version.

Go to XDA-Developers, find your device's forum, and download a verified LineageOS 11 (the continuation of CyanogenMod). It has the same look and feel as KitKat but with community backports for basic security.