To keep the integrity of each document as it was when it was published, cloud upgrades will not impact existing documents. The UI change in the last upgrade was only for the default table template, it was not intended to change tables within documents.
If this is a feature you would like to see in future releases, I would recommend creating an idea for it here Ideas for Jive. This would allow others to vote on the idea and help gain visibility with our products team.
Hope this helps.