Iconify 2.X.X introduces breaking changes, here's the full list:
In build file
compile 'com.joanzapata.android:android-iconify:1.X.X'
->compile 'com.joanzapata.iconify:android-iconify-fontawesome:2.X.X'
In layouts
android.widget.IconButton
->com.joanzapata.iconify.widget.IconButton
android.widget.IconTextView
->com.joanzapata.iconify.widget.IconTextView
android.widget.IconToggleButton
->com.joanzapata.iconify.widget.IconToggleButton
In code
com.joanzapata.android.iconify...
->com.joanzapata.iconify...
Iconify.IconValue.fa_something
->FontAwesomeIcons.fa_something
- Nothing in
Application
class ->Iconify.with(new FontAwesomeModule())