Does waves node software compulsorily force the node operator to rebuild the chain data?
Question is not clear enough for me. Which scenario do you mean here? Could you give more details?
For example, my present node running v 0.11.1 if I run a future version like v 0.19.x would 0.19.x in the future force me to forsake the mainnet chain data and rebuild the chain from height 1?
I am speaking in the context of me forking waves at KatalystDEX.
Yes, since sometimes we change format of node’s internal storage most probably you’ll have to rebuild state.