Does submitting two (substantially different) versions of a same paper count as dual submission? To be specific, let me take this as an example:
Say I've done a research and a paper A was written about the research. However, later I found that I can make some improvements on the method of A, and after making these improvements I've got B, a second version of A. A and B are same in their abstracts, introductions and related works, but largely different in their methods and experiments. I've submitted B to conference X which will inform its final decision to authors in late June and I'm going to submit A to another conference Y whose submission deadline is in late April.
Question is, will this be considered as a dual submission? If the answer is positive, then which part(s) of the content of A should I modify to avoid such a problem? Thanks.
Note that my field is Computer Science, and most conferences in this field consider their proceedings as publications.