I am running Cyanogenmod 12.1 in LG G2. I would like to change the boot animation.
Does the system support this feature?
If you change Theme (Settings > Theme), you can select boot animation as one of the attributes from that theme to update.
I use the boot animation from one theme and other attributes (icons, fonts, colors) from others.
In Play Store, you can usually see a small preview of the boot animation in the screenshot section. Search for "12.1 theme".