For Revamp jobs which code release is applicable?

Hi all..
I am currently (2015) working on a revamp job which was constructed in year 2006.
Now, we have to add tappings to the existing lines for which stress analysis is required. The old C2 native files are available.

My question is:
1) Which years ASME 31.3 code needs to be applied for the new lines?
In my opinion the old code shall be applied for the new lines too, plz confirm...
2) In case we apply the new code to the new lines, there may be failure or design changes which may be required to the existing piping.

Please reply and also share on any other considerations for such revamp jobs.

Dear all,

Pls share your experience...

Client specifications apply. Typically they say "latest code." If it fails, find out if what you're doing exacerbates the issue or not. Advise the client, and let the client decide if they want to continue.

Thanks Michael.