Originally Posted by
Fabo.sk
Just a note to those not familiar - any economy class can exist as Light, Classic and Flex (including Y light and K flex, yes), every Business class can exist as Saver and Flex. And I presume they might have a similar system in First but I don't know.
First does not have that system as far as I know, and certain letters do not offer saver: for example J. Although it could be that it’s just extremely rare.