I came across this strains chart and was wondering what they effectively mean. Is the virus significantly different, is it like flu and will have many versions? They listed no amino acid mutations towards top of detail, is this a key detail?
The strains are specialized for some group of animals. This strain was specialized for another animal, and it jumped to an human host.
The virus will accumulate mutations slowly. Most mutations are irrelevant. They are useful to track how the virus moved from country to country, but these mutations doesn't change anything for the infected person.
But some mutations may make the illness more deadly and other more mild.
Also, other mutations (or accumulation of mutations) will make the antibody for version X not useful against version Y. So getting a lot of people infected or vaccinated against version X does not give protection or herd immunity against version Y.
This is what happens with the flu. There are many different versions that are different enough, so you need a vaccine that have the versions that the doctors guess will be popular this year.
Does the covid19 have two versions that are too different and getting infected by version X doesn't prevent you from getting sick again with version Y? Probably not yet.
Will the two versions develop before the pandemic is controlled/eradicated? I don't know. My guess is that virologist can have a good guess because it is very similar to other virus they know, but I have not reed any convincing article for yes or for no. It will be an informed guess anyway.
If the virus is not eradicated, but only contained, do the people in risk groups need to take a new vaccine for the version that will be popular that year? I guess yes. At least until the virus mutates to a not deadly version that flies under the radar, like all (most) of the other versions of cold.
(The technical term for versions probably is strains, but I'm not sure of the exact definition of strains, substrians, subsubstrians, family of strains, or whatever is the correct classification. So I prefer to use a version to make it more fuzzy.)