According to 现代汉语词典:
- 答复
回答问题或要求
对问题或要求做出的回答
- 回答
对提出的问题、要求给予解答或表示意见
对提出的问题、要求所作出的答复
For me both seem to be practically the same. One uses the other in its explanation.
At least for me, it feels that 回答 is a more general word while 答复 is more formal, and usually used when it involves someone superior. But I'm not sure if this is correct.
So I wonder if there is any difference between them, on its usage as verb.