Post another question about the new problem, referencing the old one to avoid duplication of effort and narrowing the problem space down. So in the general good question style: "I've had problems with A and /this/ fixed it, but now I have an additional constraint B and need help with adapting the model. I've tried C and D, but ...".
In my case, upvoting a question is also because of how the system is presenting the upvote. If you look at the question upvote, it says :
the question 1) shows research effort, 2) it is clear and 3) it is
now if you look at answers, it says :
the answer is useful
So there are 3 conditions to upvote a question, and only one to upvote an ...
Option (#) 1 is out of the table, because it would be an "attempt to reply" (custom reason for rejecting edit-suggestions from <2k users) and could also be considered a "conflict with the author's intention" (another custom reason).
This leaves #2 and #3. A nuance from the way the question is written, I'd suggest you going with number #2, but #3 is also ...
The question author or anyone can edit and post a cohesive answer compiled from the comments with an optional addition of his/her personal research.
Answering you own question is encouraged.
Consistently Answering your Own Questions
This is very much case by case advice but, I think what I would do is to try and edit the original Question, and possibly some or all of its answers, to make it explicitly clear that they apply up to a particular version or time. This should be done carefully so that their content remains at least as relevant to the Q&A as it did when written.
I would ...
The answer to What can cause a question to be bumped? on the Meta site explains all the ways a question can be bumped.
In my opinion, there are circumstances where an accepted answer may not be the best answer. If a question is bumped years later, someone may have a better solution. The asker has the option of accepting that answer instead.
Is there a way ...
There is no reason why this question and its answers would "eventually get closed and disappear" unless the question and both its answers start to receive sufficient downvotes to take away their positive voting record. To assist their survival (which I think is in no doubt anyway) I upvoted both answers. If there had been a reasonable code attempt in the ...
A key difference between a focussed Q&A site like GIS SE, and a discussion forum or other styles of Q&A sites is that old questions with answers are considered just as valuable as new ones. This is because our Q&As are more like wiki pages where the content can be constantly improved.
Improvement to Q&As can happen for many reasons like: