Per Wiki, the SU-24 was first flown in 1966 and introduced into service in ‘74, and is primarily a bomber.
Not state-of-the-art by any means, and certainly not a fighter.
But when was the last time Russian pilots *had* to fight anyone?
Their favorite targets are guys riding mules carrying muzzle-loaders.
I think Russia will step up attacks on the anti-Assad rebels rather than bow to the Obama coalition demands.