Same mapping over the index in elasticsearch

I am working on a project which is currently using elasticsearch 1.4, Now we are going to upgrade elasticsearch,We have so many field which have different mapping on different record type .

We have some common field on different record type and have different implementation as per our requirement so they have different mapping as well. Is there any way to have different mapping over the same index?

Is there any meaning to make field mapping nested type which just require type string?

To what version you're upgrading ?
Have a look to Templates. I'm using them for langage analyzers (and marvel indices)
here's the official doc :

I am upgrading to 2.3.3 version.