Unofficial TEMASEK's CyanogenMod 12.1 ROM for Redmi 1s is OUT !!! Lollipop 5.1
and it is based on Cyanogenmod the Android Open Source Project with extra contributions from many people within the Android community. It can be used without any need to have any Google application installed. Linked below is a package that has come from another Android project that restore the Google parts. CyanogenMod does still include various hardware-specific code, which is also slowly being open-sourced anyway.
ALSO READ>>[REDMI 1S] MOKEE 5.0.2 ROM [LATEST]