This I can't tell, as am still surprise as well. Just checked bitcoincore.org, and it seems true. I believe a review will come up soon on the forum.
Nobody knew about this new version v26.2, but I'm on version v27.0, so OP, why not use the latest one?
Bitcoin Core is stable software, so versions released in a short space of time won't have much of a difference, other than minor bug fixes, but always read the changelog for more details on the version you are downloading.
But anyway, I don't recommend downloading from version v23 downwards, always download the latest releases and follow the release notes.
Yes, that makes sense. Perhaps the legacy wallets are no longer supported. Or the option to import non-HD wallets. Although I don't read anything about removed functionality in the release notes of 27.
If you have a legacy wallet, you can migrate it to the new descriptor format, so your private keys from the legacy wallet will be included in the new master key pair, so you must make a new backup to keep your wallet updated. You can still load legacy wallets.
Remembering that we can't confuse legacy wallets with non-HD, as both legacy wallets and descriptors are HD (hierarchical deterministic) wallets. HD means that addresses are generated by the BIP32 master key infinitely deterministically, the generated addresses always belong to the master key.