How to upgrade to 1.7 restoring old datas from corrupted website

[eraser80]

Hello everyone, I am writing in this forum because I am quite desperate because the website has been offline for a few days due to something I do not know how to solve ... I try to retrace the steps ...

a few days ago I realized that the back office and front office of my website was offline ... after promptly contacting my hosting provider's assistant I discovered that the reason why my website was not working was because it was not compatible with newer versions of PHP (7.3+).
When they first announced that they will be discontinuing older PHP versions, they stated that we will give by the end of 2021 for customers to make their websites compatible with newer PHP versions.
they gave more than enough time for all pending updates to be handled, exactly due to the fact that once the time comes for older PHP versions to be removed, this change cannot be reverted or postponed.
PHP versions, which are older than 7.3 are no longer available on our servers.
They suggested to me, In order to be able to make my Prestashop 1.6.1.13 website compatible with newer PHP versions, I would need to update its core and components. and they said that the oldest Prestashop version that supports PHP 7.3 is 1.7.7. The Prestashop version 1.7.8 supports PHP 7.4.

Now the problems...I tried to upgrade my prestashop to the latest version 1.7.8.5 and after several attempts I was able to update and log in, but after checking if all the products and all the orders were present, after some operations in the back office it is the blank page returned and the site went offline ...and I recieved different rorroes about php...I think that something is corrupted o non compatible... and after activating now I ask you ... is it possible to do a new clean installation on the same domain as the latest version of prestashop renaming old folder installation and then import the old data (images, orders, customers, products and all settings)? I hope that some of you experts can help me because I don't know what to do anymore ... thanks in advance to anyone who can give me some tips and help me solve this problem. Excuse me if I have dwelt too much

[knacky]

The problem with upgrading from 1.6 to 1.7 is very extensive. There are modules that can do this upgrade, but none of them are perfect. 99% of users who have performed such an upgrade have constant problems. In your case, the most sensible solution is to hire someone, otherwise you run the risk of losing all your stored data.
If it is no longer possible to run PS 1.6, you need someone who will copy the whole e-shop to each other with support for the older version of PHP, create a clean installation and transfer all the data to the new installation. Of course, you will need to create a new template, install new modules, etc ...

[knacky]

You can do everything yourself. There is software for the computer on which you create local web hosting. For example, WAMP.
You will have an old Prestashop from which you can import data.