From the Qatar Airways Instagram page:

"Our Premium Class passengers now have more time to enjoy out in-flight amenities. with our new Pre-Select Dining service, you can book your main course meal at least 24 hours before your flight. It will be available for select flights from Doha, with more added later in the year."

Apologies for the lack of a link to the Instagram post but I cannot access it on my work computer right now.