I have been asked this question a long back by one of my net friend that he needs to test 3 different things in the next release i.e
·         Enhancement for already existing feature
·         New requirements
·         Resolved issues.
 
So how should I proceed to test & what should be the order to test everything?
This is a good question & I think in current agile word of software development it happens.
I would suggest that in this situation, there should be a risk assessment considering the time frame you have, for the next release & then take decisions that what to do test first.
Ideal order in my view for the above scenario will be, to test the new requirements first followed by testing the enhancements for already existing feature in project/module & then finally doing regression test to verify the resolved issues & stability of the application.
The order that is taken above will depend on the risks and time frame available.
I hope, this would help in taking decision in the scenario explained above.
 
Happy Testing,
Cheers ,
Javed Nehal