How long will legacy wallets be supported?
They are planned to be dropped entirely in 27.0, which will be released in ~7 months. However there is and will continue to be a tool in Bitcoin Core that allows you to convert a legacy wallet into a descriptor wallet.
I have few question,
1. By "convert a legacy wallet...", do you mean all kinds of legacy wallet or just HD legacy wallet?
2. By tool, do you mean CLI tools just like
bitcoin-wallet binary?