Lollipop replaced the old Dalvik VM with ART, making apps run faster and more efficiently.
For very old hardware, official download links may be dead. Searching Archive.org for specific ROM filenames found on XDA is a common workaround. Step-by-Step Installation Guide update android 44 4 to 50 download patched
Upgrading via a patched ROM is a "clean install" process. Before you start, ensure you have: Lollipop replaced the old Dalvik VM with ART,