Hi everybody, simple question but as we all know a very tricky one 
We need to up date an old oxid shop 4.5.1 to the current version, has anyone experiences with such an up date? Possible problems? The shop should not be offline for to long…
If its recommended not to do a direct up date, please write some sugesstions, thank you.
Christian:)
sure, somebody has experience.
actually there are lots of possible problems that could occur during the update: an Alien Spaceship could destroy the earth or just steal your server,
you could forget to make a backup
russia could start the third world war and destroy your server,
your modules and theme will not work after update
a plane could crash into the building where your shop is hosted
your computer could crash
you could accidently delete the lvie database
chinese invade you country
diarrhea
allopecia
you could sart update directly on the live shop and kill it and take it offline for 2 weeks and get fired
zombie apocalypse
oh, did i mentioned the alien spaceship?
make a backup,
get a test shop where you do the update,
follow the instructions,
use forum search
use google search
that will cover 99,9% problems that could occur during the upadte, even the zombie apocalypse
Did you mention the alien spaceship? 
Ok ok, he is right: Make a plain copy of your system an run the update as often as possible. Update your modules (you need to add metadata.php files,…) try it, optimize the process an in the end you will need only a few minutes.
Other option is to plan with a delta data-migration. Then you update your copy, make that version live and afterwards you migrate the data that has changed in the meantime. For that you need a deeper knowledge of OXID but you could update without any downtime.
Best regards,
Joscha