This is true, but despite this, depending on what writing style or audience you're targeting, singular "they" may still be considered incorrect. Also if you're

This is true, but despite this, depending on what writing style or audience you're targeting, singular "they" may still be considered incorrect. Also if you're in the US, the use of singular "they" can be intertwined with certain politics and legislature, but that only matters for legal documents and government publications. For casual speech, though, singular "they" is certainly correct and widely used.