Few days back Miromax Yu Yureka Got unofficial Cyanogenmod 13 Rom you can check it from here.Today Yu Yuphoria (lettuce) get an unofficial built of Cm13 ROM based on android marshmallow 6.0.Now you can update your yuphoria to android marshmallow 6.0 by flashing Cm13 rom in it as of now the rom has few bugs in it that are Data connection not working in it where as sims are working fine and audio part is also broken in it else everything is working in it.
4.Then flash CM13 android marshmallow rom and gapps from recovery in it.
If you want to install cm 13 in yuphoria for trial use then you can flash Cm13 via custom recovery in Yu yuphoria by following below steps on How to install Cm13 rom in Yu yuphoria.
#Requirements
1.Your device must have Custom recovery (CWM or TWRP)
2.Make sure to make backup or you data and current rom.
3.You can check for more bugs and working report from XDA Thread.
#How to Install Cyanogenmod 13 on YU Yuphoria
1.Download CM13 Rom for Yu Yuphoria and the appropriate Gapps 6.0 package from link given below Copy it in your in your device.
2.Now place the Cyanogenmod 13 rom and gapps 6.0 zip file in sd card.
3.Now reboot to Recovery mode.
4.Then flash CM13 android marshmallow rom and gapps from recovery in it.
5.Now Clear cache and Clear Data.
6.Reboot your device.
Done! you just flash cyanogenmod 13 rom in your Yu yuphoria.Enjoy Android Marshmallow 6.0
Bro This Just experimental thing.
A lot of stuff not working.
The audio and data are major bugs!
Waiting for the nighlies!!
then wait for 6 months or more !