These UE categories are often referred to as UE classes. The low end UE does not support MIMO but the high end UE will support 4×4 MIMO
Whatever category a UE belongs to, it has to be capable of receiving transmissions from up to four antenna ports. This is because the system information can be transmitted on up to four antenna ports.
It should be noted that some of the capabilities are outside the UE category info. For example the Inter-RAT capabilities like the support of EV-DO or GSM, etc is not specified as part of the UE categories.
Similarly the support of duplexing schemes and the support of UE-specific reference signals are outside the scope of this.