So I know that compileSdkVersion is the version of the API the app is compiled against. While targetSdkVersion is the version the app was tested against.
I am using a library which requires some attributes present in a higher API version for which I need to update the compileSdkVersion else I get build errors. But I don't want to update the version of the support libraries or the targetSdkVersion. Will this have an impact on how the other features of the app behave? Can I expect to release the app with surety that other features won't break?
Will this have an impact on how the other features of the app behave?
It could only impact on a library, which wants higher API. At runtime you could check version API and skip some operations, but your case inside a box (lib), no way. However, some of classes could be deprecated or even erased in the next releases of android support library.
Iak Lake wrote a good topic about compileSdkVersion vs minSdkVersion vs targetSdkVersion. Here is a link.