Is it normal to keep changing research objectives in PhD? During my first year, my supervisor advised me to have four objectives that lead to four contributions to the research.

Throughout the journey, until I'm now on my final year (in computer science), I realize myself to keep changing my objectives as the needs of the research keep evolving. And, as the research has evolved, some objectives do not make any sense due to some reasons such as it's not so significant, too simple, and redundant.

My supervisor is always asking how many of objectives (out of four) that I have achieved so far? I can't really answer as it has changed from my first to second, to third a year.

So my question is, is it normal if I keep changing my objectives without sticking the those I outlined during my first year? And, it is still okay to change objectives when I'm now in my final year?
So my question is, is it normal if I keep changing my objectives without sticking the those I outlined during my first year? 


Yes.  It would be unusual if you did not improve your objectives.  Improved objectives is a symptom of improved research.


  And, it is still okay to change objectives when I'm now in my final year?


It's not okay to start your research over from scratch when you do not have enough time to complete new research.  It is okay to discover that your existing efforts achieved goals you didn't think of when you started (but scientists should avoid data dredging).  In other words, it depends on the details.