From the MH website:
From tonight, 5 January 2016 (until further notice), the airline will only be able to accommodate cabin baggage of up to 7kg – one piece totalling 7kg per Economy Class passengers and two pieces totalling 14kg (up to 7kg per piece) for Business/First Class passengers. Passengers who wish to check in their luggage will be able to do so, however their baggage will only arrive later.
Full announcement:
Temporary Limitation on Checked In Baggage Allowance for Kuala Lumpur-Europe Sector
Personally, I'm curious why they aren't doing an en-route fuel stop. Yeah, it's logistically a pain, inconvenient for passengers, but it's not a deal breaker.
Not taking my bags and limiting Y pax to 7kg of carryon until my bags show up at some random point down the road? Now that's a deal breaker!