J3/VM3.8/PHP 7.4 upgrade strategy

[EvanGR]

Hello,

I am maintaining a store using older (but well functioning) versions:
Joomla 3.10, VM 3.8.8, on PHP 7.4

The time has come to upgrade to modern versions, mainly for security reasons (we want to move to PHP 8.3+).

Assuming the site does not have any 3rd party extensions (to keep things simple), how would you split the update to stages, and what would those be?

For example, update Joomla first to v4? Then update VM?

Perhaps just setup a new clean J4/VM4 site, and migrate just the data?

Is the DB schema the same between VM 3.8 and VM4.x? (so maybe we can simply copy the database over?)

What about PHP? At what point do we change PHP version?


Also, since the update will be quite complicated, my preferred approach would be to create the updated site locally over a period of days or weeks, and when we're ready and well tested, I want to be able t update the live site fast.
This will require migrating the live data (customers, orders etc) in a very short amount of time (say, within an hour or so), so as not to disrupt the service.

Thanks in advance!

[Ghost]

Update VM first, then Joomla. VM4 supports J3 but VM3 does not support J4. If you really have no 3rd party extensions, upgrade should be easy. But always make a backup anyways. Template will probably need updating/changing too.

[iWim]

Also I recomend doing the update locally first.
Then you'll know what to expect and you can safely check if everything works as expected (Don't forget your template!)
If something needs extra work or something goes wrong, your live website is not affected.

Install WAMPServer or MAMP on your computer.
Create a backup of your webshop (Akeeba Backup)
Unpack/install your backup in WAMP/MAMP (Akeeba Kickstart)

[PRO]

do this locally first. OR a private copy of the site in a folder etc.

I would take a clean install of the new vmart, and then move the virtuemart database over, thumbnails, files etc. then update/migrate etc.