I googled around and it says that you cannot use anti aliasing(like txaa mfaa etx) with deferred shading?
It does support AA, you can use FXAA or temporalAA
Is there any other way to implement other types of AA such as MSAA or MFAA?
Yes you can.
I have done it in the past (can’t really talk about it due to NDA) and it is fairly straight forward.
Modify EAntiAliasingMethod (Scene.h), make sure to pass it correctly (see FSceneView) and add a custom pass to the post-processing (postprocessing.cpp)
Note that you will have to do some fiddling as some post processes do slightly different things based on the type of AA.