The days of CyanogenMod are officially behind us as Lineage OS continues to chug along. While it is not the same it does provide us with what we needed from CyanogenMod which is a pure Google Android experience on devices that otherwise include an OEM skin. One of the main features of CyanogenMod has been the inclusion of the Theme Engine. Theme Engine themes are able to theme every aspect of the rom including the framework. Over time Substratum, based on Sony's Overlay Management System, has really begun to gain ground and many CMTE theme developers had moved their talents over to it.
CyanogenMod Theme Engine may be dead according to sources. During a chat between "sykopompos" the lead developer of Substratum and Lineage it was stated that "Clark" has moved on from CMTE. The fact that Lineage is having talks with Substratum's lead developer is not good for CMTE. It could still be merged into Lineage, but it looks like this is the end for the popular theme manager.
via XDA