As to updates (and other aspects of API design too), I highly recommend taking a look at the solutions proposed at https://aip.dev - e.g. in case of update, https://aip.dev/134 - note the use of FieldMask (though there's some slight not-yet-resolved inconsistency observed recently by one user: https://github.com/aip-dev/google.aip.dev/issues/673)