I bought a new bottle about two months ago, so I assume it is still being sold.
That noted.....I am not an expert by any stretch, but,
I have used it successfully at full strength for ich tx without any noted side effects (and a "cure" in two-three days).
The few live corals, my anemone, and crabs/snails in my tank have never showed any signs to indicate that they were bothered by the tx.
Hope this info helps you.