I just purchased an SDS2104X Plus, at Software 1.3.7R5, FPGA 2020-09-23, CPLD 03, Hardware 02-04. Using "SDS2000X+" for Model, SCOPEID sans hyphens in dual case, options updates went trivially easily.
Note, I don't see much difference with the 500MHz update except the 0.5nS/Div horizontal position and less high-frequency cutoff than at 350MHz. It's interesting to have more than one choice for limited bandwidth! (Was On/Off, Now Full/20M/200M).
Picture is a fast-rise-time pulse (avalanche 2n3904 at 160V). The peak at 350MHz (11.25V) was a little smaller than at 500MHz (13.6V). With only 10 dots on the entire screen, I'm not certain how useful the 0.5nS/Div setting is, but it makes my 5nS-rise-time signal generator (SDG1062X) ramp look quite flat!