Hello everyone!

As you know, because of the current corona situation, flights keep changing frequently.

I purchased a ticket with Turkish Airlines on business class (semi-flex), where I got for all my flights the class "J".
However, as one of my flights had schedule change, I needed to select a more suitable flight, which I couldn't perform online, rather through customer care center.
But after changing the flight, I noticed that the flight has now a class of "K" instead of "J".

The customer service told me, that this is yet a business class and shares the same fare options of Lounge, Baggage and seats. But I did not ask about refund and cancelation fare.

Anyways, as you probably had experienced such a thing, I wanted to ask you: what are the exact differences between these two classes? Which one is better? And have I lost any advantages with this change of the class?

Thank you very much!