kali-linux-2017-W22-amd64 Persistence USB update usb to kali-linux-2017-W23-amd64

[tdbone1]

so i have my kali-linux-2017-W22-amd64 Persistence USB working perfect.
i have done some apt-get update ** and apt-get upgrade and also i download small files with firefox off internet (to my documents mostly)
anyhow i use it just like a full drive install (working great, really love this live rolling versions)

i do however like to keep current as im on a metered connection (mobile hotspot with 4GB data plan) so when i get the chance to download a new version of kali rolling off a non-metered connection i do it so i just grabbed amd 64 week 23.

now the big question is
how do i update/upgrade my usb stock without losing all my data that i have accumulated in the last week?
i want to preserve everything if possible

i have googled but it seems what keeps coming up is how to actually install a fresh kali-linux iso to the live usb stick each time which in turns formats the stick during this process.

any do's and dont's would be great to know.
i dont think i just want to copy the documents dir and do a fresh install because i think then i would have to re-partition everything and make drive persistent all over again.

do i just extract the iso and copy the directories over to ths currently installed files that (are older)?

thanks

[Mister_X]

updating your thumbdrive does just that: apt-get update && apt-get dist-upgrade

The reason why there are weekly ISO is to get updated packages on a live ISO (and it fixes bugs presents in packages that were in the stable release) and not everybody is using persistence. Live is pretty convenient too.