I discovered that shadows in 2.81 look noticeably different or even worse than in 2.80. Both have soft shadows enabled. Here you can see the project in which I discovered it: there is this big flat black area, that seems not optimal to say the least (2.80 left, 2.81 right) And then I made another test with the default cube, so anyone can recreate it. While for 2.80 it looks quite natural, you can see the sharp and pixelated shadow samples for 2.81. Keep in mind that this is with soft shadows enabled for both versions. Does it look like that also for you? Is there a new setting that needs to be tweaked or what's going on?