Existing Honeywell 5800 series RF sensors could be reused with the 345Mhz version of the IQ Panel 4 found here:
The existing keypads and Vista panel would not be used, but you could reuse wireless sensors directly on the new panel, and you could either replace wired sensors if there are only a few, or if you want to reuse wired zones you could do so with a hardwired translator below: