Use APKPure App
Get Yu Support old version APK for Android
Your one stop solution for ROMs, Kernels, Recoveries, etc. for your Yu.
Using this app you can easily browse through various Roms, Kernels, Recoveries, Tools/Utilities, Official Yureka forums, call centre info, etc.
Thus, all-in-all it is your one stop shop for everything related to Yu.