android - windowBackground Material design compatibility -

i following material guidelines

the problem windowbackground not available below api 21 (at least think)

• is generic way know in api attribute has been added?
• is there way know attributes must put appart mantain compatibility?( can use colorprimary in values , values-v21, cant use windowbackground on values)

android:windowbackground has been added in api level 1 it's available in every android version.

in order check whether attribute available specific api-level can check r.attr page of android developer site. there can see possible attributes api-level in added (top-right corner).