Haven't heard of any additional Android compatibility... good question, would be interesting to know if there are any Android Apps that didn't work before that work now.
But from what I understand most of the issues with Apps that don't work are
1) Google Services - and 10.3.1 didn't fix that.
2) Database / OBB Files that need to be downloaded after the apps is installed - I know two apps I want still don't work because of this - one I can trick by downloading the info and putting it in the OBB folder, until the next month update kills it again.
3) Older Android Apps that just aren't compatible - even with newer Android Devices, so I doubt that is a 10.3.1 capability.