Is there any function to get historical versions of a document? ...

No function OOTB as far as i'm aware. You could look into the API and create a custom function for this purpose.
forum.appian.com/.../

The historical metadata you can get it with this plugin
community.appian.com/.../get-document-version-metadata

Using the above component you will able to get historical data but there won't be any way to download the historical document in UI

Hi shaoyongw  as per my understanding, if you want to deal with historical versions of a document, in such case you should go for implementing your own content management system in appian, where you can add , delete, update the document and their respective versions, but if you are not interested in doing this, then preferably you can go for content management tool, such as Alfresco

But I believe it shouldn't be that difficult to build your own custom content management system, if time permits.

Hope this will help you.