1.6 to 8.1 and new theme

[ale123]

Guys i'm here to get some help.

The situation is this: a working PS 1.6 (thitybees to be honest) with some custom modules (made by us) and some custom themes (customized by us).

Customers told use to renew the webstore, so we plan to install a brand new store with PS 8.1, develop new modules, new theme and so on.

Up to this, it's simple. Just make a test environment, develop everything and go live when done.

BUT

how can I move the old data (a lot, more than 10k customers, 5k products, ...) from 1.6 to new new 8.1 ?
I can clone the 1.6 to the test environemnt, upgrade the test from 1.6 to 8.1 and develop there, but as soon as we need to go live, i still have to merge the changed data (orders, customers, ...) from the 1.6 to the test server. how ?

I can develop a brand new 8.1 on a test server and when It's time to go live, i can copy the full prestashop dir over the 1.6 and run the autoupgrade ? Or copy a fresh 1.7 install over the 1.6, run the autoupgrade and when done, copy the new and customized 8.1 over the 1.7 and run the autoupgrade ?

Should I skip the upgrade step and use some tool to migrate data from 1.6 to the new 8.1 ?

Better ideas ?

[ComGrafPL]

If you make a clean 8.1, set up modules and theme. Migrating data ( orders, customers, products, images etc ) you can use module, service either try with manual data base work.

Updating 1.6 to either 1.7 / 8.1 using 1-click isnt best idea. Better use clean 8.1.